Fix todos page mobile viewport layout

## What does this MR do?
Fixes the todos page mobile viewport layout

## Are there points in the code the reviewer needs to double check?
Shouldn't be any :thumbsup: 

## Why was this MR needed?
Improve GitLab usability on mobile devices

## Screenshots (if relevant)
Before:
![Simulator_Screen_Shot_Sep_13__2016__11.30.19_AM](/uploads/7053a1bb1fca6238c5f86d671bf96ff0/Simulator_Screen_Shot_Sep_13__2016__11.30.19_AM.png)

After:
![Simulator_Screen_Shot_Sep_13__2016__11.30.04_AM](/uploads/a30921c1a1118655b547977872e8e1c7/Simulator_Screen_Shot_Sep_13__2016__11.30.04_AM.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [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)

## What are the relevant issue numbers?
Closes #22097

See merge request !6325

Skip wiki creation when GitHub project has wiki enabled

## What does this MR do?

When importing a repository from if the repository has wiki, we should not create the default wiki. Otherwise the GitHub importer will fail because the wiki repository already exist. This bug was introduced here https://gitlab.com/gitlab-org/gitlab-ce/commit/892dea67717c0efbd6a28f7639f34535ec0a8747

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

No.

## Why was this MR needed?

GitLab fails to import GitHub Wiki.

## 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
  - [X] Added for this feature/bug
  - [ ] All builds are passing
- [X] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [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)

## What are the relevant issue numbers?

Fixes #22225

See merge request !6665

Adds v-pre to code blocks in comments

## What does this MR do?

Allows users to comment on discussions with code that contains `{{`

Previously because of the discussion part being a Vue app it was being converted by Vue & therefore creating JS errors & the code not displaying correctly. This adds `v-pre` onto the code element to allow the user to write code that would contain `{{`

## What are the relevant issue numbers?

Closes #22911

See merge request !6674

If the GitHub project repository has wiki, we should not create
the default wiki. Otherwise the GitHub importer will fail because
the wiki repository already exist.

This bug was introduced here
https://gitlab.com/gitlab-org/gitlab-ce/commit/892dea67717c0efbd6a28f763
9f34535ec0a8747

Update RuboCop to 0.43.0 and update configuration

`Style/VariableNumber` is explicitly disabled because I don't think we
care if we name a variable `var_1` or `var1`.

See merge request !6670

Restrict failed login attempts from users with 2FA enabled.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/19799.

See merge request !6668