Clarified who can push to a protected branch

Changes include:

- Added front matter

- Added Troubleshooting header

- Shorted long lines

- Corrected typos and improved clarity throughout

Edits to conform with CE epic 1280 SSOT standards, other improvements

Move issue board models to boards directory

Closes #61293

See merge request gitlab-org/gitlab-ce!29260

Some classes in vue_shared were used only by boards, so they were
moved to the boards directory.

Allow masking if 8 or more characters in base64

See merge request gitlab-org/gitlab-ce!29143

Fix migration specs using factories

Closes #62911

See merge request gitlab-org/gitlab-ce!29350

We need to stub default_git_depth and default_git_depth= because some
old migrations specs try to create a record using schema before that
column was introduced.

The `let!` calls were executed before the `before` hook which still
caused some factories to fail, so they're created in the `before` hook
now as well.

Add task count and completed count to responses of Issue and MR

See merge request gitlab-org/gitlab-ce!28859

Improve email text part

See merge request gitlab-org/gitlab-ce!29111

Remove extraneous DiffNote#supports_suggestion? calls

See merge request gitlab-org/gitlab-ce!29027

Add project level git depth setting

Closes #59688

See merge request gitlab-org/gitlab-ce!28919

Migrate legacy uploads

Closes #57217

See merge request gitlab-org/gitlab-ce!24679

Add dependency list documentation

See merge request gitlab-org/gitlab-ce!29307

[CE of Part 2] 5276 Update existing stores for file terminal sync

See merge request gitlab-org/gitlab-ce!29333

[CE of Part 1] 5276 Remove 'build-page' from 'ide-terminal' element

See merge request gitlab-org/gitlab-ce!29331

Add spec for task_completion_status

Add test cases for task_completion_status result

Extracted shared samples

Add new spec file for task completion status response

Fix style errors

Add changelog entry

Changed samples to Hashes

Remove test for successful request

Remove not nil expectation

Add task_completion_status to api documentation for issues

Add task_completion_status to api documentation for merge_requests

Refactor spec so it just requests one specific item

Add task_completion_status to Taskable

Simplified task completion status in entities

Refactor spec so it separates status code check and content check

Fix spec description text and field name

added code differences from EE to CE

Closes gitlab-ee#10088

See merge request gitlab-org/gitlab-ce!29271

Remove metrics_time_window feature flag

Closes #62091

See merge request gitlab-org/gitlab-ce!28670

SSoT audit fixes for some topics in CI section

Closes #61505

See merge request gitlab-org/gitlab-ce!28957

Implements part of the single source of truth audit
fixes for the CI section.

Integrate demo link into content more

See merge request gitlab-org/gitlab-ce!29242

(CE Port) Onboarding helper component

See merge request gitlab-org/gitlab-ce!29133

- Add styles for popover
- Add $accepting-mr-label-color to color variables

Add git 2.21 install from update_source

See merge request gitlab-org/gitlab-ce!28836

- On CMD+S when editor is focused
- On editor blur
- When file is created in tree
- When file is removed in tree
- When file is renamed in tree

Hide operations icon in small screens

See merge request gitlab-org/gitlab-ce!29230

CE Port

**Why?**
The styles applied to `.build-page .top-bar` were mostly
unecessary for the IDE terminal. The static positioning might
have also been causing a strange line to show up in the terminal.

Improve Jira Server documentation

Closes #58975

See merge request gitlab-org/gitlab-ce!28463

Fix OpenID Connect documentation

See merge request gitlab-org/gitlab-ce!29314

Make OpenID Connect work without requiring a name

Closes #62208

See merge request gitlab-org/gitlab-ce!29312