Robots and browsers should not crawl and remember deploy page

## What does this MR do?

Changing meta information for robots and browsers not to remember a page during deployment

## Why was this MR needed?

User browsers and robots takes the page content as accurate during deployment - HTTP code 200 is send to browser, it's all being remembered.

See merge request !5842

Update sprockets version to 3.7.0

Closes #22277

See merge request !6489

Update robots.txt disallow to allow users/groups starting with "s"

## What does this MR do?

Update robots.txt "Disallow: /s" line to "Disallow: /s/"

## Why was this MR needed?

Currently any Project that is under a username or group name that starts with "s" cannot be indexed because of this disallow line.

For example on https://gitlab.com looking at the projects with the most stars there is this project: https://gitlab.com/somerobots/Trident

If you do a Google search for "site:gitlab.com Trident", the project comes up but with "A description for this result is not available because of this site's robots.txt"

Adding the trailing slash will still disallow all snippet short urls, but start allowing projects where the URI begins with "s"

See merge request !6481

Fixed a broken documentation link to the wiki-specific-markdown.

## What does this MR do?
Fixes a broken link

## Are there points in the code the reviewer needs to double check?
Well, it's a one line change, so it couldn't hurt, right?

## Why was this MR needed?
Because broken links make us look like chumps. :)

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?
Probably not.

## What are the relevant issue numbers?
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/21760.

See merge request !6117

Keep API mounts in alphabetical order

## What does this MR do?

Just a cosmetic change to keep the API mounts in order.

See merge request !6515

Fixes issue with rails reserved keyword type exporting/importing services.

The attribute `type`in services was being ignored by Import/Export. Added `type` as a method call in the export, as `type` gets ignored invoking `to_json`, manually adding this as a method in `import_export.yml` solves the problem. 

On a different note, I found assigning a title directly to `CustomIssueTrackerService` didn't play very well with `prop_accessor`:

```ruby
> CustomIssueTrackerService.new(title: 'asdf')
NoMethodError: undefined method `[]=' for nil:NilClass
> CustomIssueTrackerService.new(title: nil)
NoMethodError: undefined method `[]=' for nil:NilClass
```

This was also causing the Import/Export to failed... So I added a custom setter that fixed the problem.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/22461

See merge request !6499

Replace deprecated Devise helper with new helper

Closes #22357

See merge request !6462

Fix trivial typo in docs



See merge request !5849