Conflicts:
	app/models/ci/pipeline.rb
	spec/models/ci/pipeline_spec.rb

Remove Grack::Auth: part 2 (LFS)

Deprecate Grack::Auth and handle LFS in Rails controllers under the Project namespace.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/14501

See merge request !5369

Refactor pipeline creation service

## What does this MR do?
This refactors GitLab CI build processing: all builds for pipeline are pre-created when a pipeline object is created. 
The builds are created with a new introduced status `created`.
The builds are then automatically promoted to `pending` when a previous stage do succeed.
This significantly simplifies pipeline processing code solving a lot of problems of lazily initialisation of previous approach (builds were created on-demand).

## Why was this MR needed?
The previous mechanism had a lot of flows (shown in related issues) in how it work, but also in code design. Removing cross model-service-library dependencies.

The current approach moves a build creation to single place `CreatePipelineService` and removes a dynamic dependency on `config_processor` significantly simplifying a build creation and pipeline processing. Pipeline processing is implemented in `ProcessPipelineService`.

This also allows to easily extend GitLab with Manual Actions which is part of 8.10 direction issue.

## Migration problem
~~This MR removes the a on-demand creation of builds in pipelines.
 Pipelines that are running and are in mid-stage (some stages started, but not all) will not be fully evaluated after application restart. 
This happens, because the code responsible for on-demand creation is removed. 
There's no easy way to migrate existing pipelines, other than doing offline migration and putting pipeline processing in migration code (which seems to be a really bad idea).~~

To support old pipelines I added a lazy initialization of builds if none is found.

## What are the relevant issue numbers?
Fixes: https://gitlab.com/gitlab-org/gitlab-ce/issues/12839
Solves: https://gitlab.com/gitlab-org/gitlab-ce/issues/18644 https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/issues/289
Allows to easily implement: https://gitlab.com/gitlab-org/gitlab-ce/issues/17010

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)


See merge request !5295

This change simplifies a Pipeline processing by introducing a special new status: created.
This status is used for all builds that are created for a pipeline.
We are then processing next stages and queueing some of the builds (created -> pending) or skipping them (created -> skipped).
This makes it possible to simplify and solve a few ordering problems with how previously builds were scheduled.
This also allows us to visualise a full pipeline (with created builds).

This also removes an after_touch used for updating a pipeline state parameters.
Right now in various places we explicitly call a reload_status! on pipeline to force it to be updated and saved.

Fix front-end for branches that happen to contain urlencoding escape characters (e.g. %)

_Originally opened at !3574 by @ewiltshi._

- - -

Adding a branch with a name like "foo%20bar" (via command-line) and setting it to the project's default branch causes the project "show" page to 404 for that project. "assign_ref_vars" unescapes the branch name ("foo%20bar" ==> "foo bar"), making GitLab look for a non-existent branch.
This MR adds logic to skip the URL unescaping step in "assign_ref_vars".

Fixes #10772, #14992, #15304.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5770

Use `File::exist?` instead of `File::exists?`

Each `File::exists?` replaced to `File::exist?`.

Since version ruby-2.2.0, method `File::exists?` is deprecated.

See merge request !5747

Remove various redundant indexes

## What does this MR do?

This MR removes various redundant and unused indexes. See c3d5c536d9c77dbe183744cb19f2cdab7ee606fd for more information.

## Are there points in the code the reviewer needs to double check?

No.

## Why was this MR needed?

Unused indexes are a waste of storage space and slow down database writes. If they are ever needed again we can re-create them. There's no point in hoarding indexes because you _may_ need them in the future.

## What are the relevant issue numbers?

#20767

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [ ] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5759

Add group members API endpoints to request access and approve requests

## What does this MR do?

Add group members API endpoints to request access and approve requests.

## Are there points in the code the reviewer needs to double check?

I chose to factorize the group/project members API as well as the new group/project access requests API.

I initially also created new services to centralize the permission checks related to actions on members, but this was out of scope and this MR is already quite big so I opened a temp MR at !5566 based on this one.

## Why was this MR needed?

To finish the "request access" feature.

## What are the relevant issue numbers?

Closes #18583.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !4833