Added options related to signed url creation to work with servcies that do not support V4 of the signature.

Ensure that spec/features/issues/user_uses_slash_commands_spec tests run locally

Closes #45970

See merge request gitlab-org/gitlab-ce!18713

See https://gitlab.com/gitlab-org/gitlab-ce/issues/45970

Platform: Use component to emit event on Subscription toggle component instead of eventHub

See merge request gitlab-org/gitlab-ce!18703

update devise 4.2 -> 4.4

See merge request gitlab-org/gitlab-ce!18667

[Rails5] Fix trusted proxies

See merge request gitlab-org/gitlab-ce!18705

CE port of "Remove `features/group_active_tab.feature`"

See merge request gitlab-org/gitlab-ce!18706

CE port of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/5554

There is a bug in trusted proxies: https://github.com/rails/rails/issues/5223
This commit adds a monkey patch to fix the bug.

Example of errors:

```
1) trusted_proxies with default config preserves private IPs
    Failure/Error: expect(request.ip).to eq('10.1.5.89')

      expected: "10.1.5.89"
          got: nil

      (compared using ==)
    # ./spec/initializers/trusted_proxies_spec.rb:12:in `block (3 levels) in <top (required)>'

2) trusted_proxies with default config filters out localhost
    Failure/Error: expect(request.ip).to eq('10.1.5.89')

      expected: "10.1.5.89"
          got: "1.1.1.1"

      (compared using ==)
    # ./spec/initializers/trusted_proxies_spec.rb:18:in `block (3 levels) in <top (required)>'
```

Update environment item action buttons icons

Closes #38755

See merge request gitlab-org/gitlab-ce!18632

[Rails5] Fix params passed to MergeWorker

See merge request gitlab-org/gitlab-ce!18701

Improve Web IDE Commit Panel

Closes #44837

See merge request gitlab-org/gitlab-ce!18234

Add pass through to stripHtml for undefined and null inputs

See merge request gitlab-org/gitlab-ce!18690

[CE] Backport Identity.uniqueness_scope from EE

See merge request gitlab-org/gitlab-ce!18689

Forking repositories is handled by Gitaly by default

See merge request gitlab-org/gitlab-ce!18679

Change font for tables inside diff discussions

Closes #45485

See merge request gitlab-org/gitlab-ce!18660

Include documentation about STAGING_ENABLED variable for AutoDevops

See merge request gitlab-org/gitlab-ce!18675

Load branches on new merge request page asynchronously

Closes #37477

See merge request gitlab-org/gitlab-ce!18315

[ci skip]

Compute repository checksum by default

Closes gitaly#1146

See merge request gitlab-org/gitlab-ce!18648

Optimize Emoji Sprite Handling

See merge request gitlab-org/gitlab-ce!18576

Initial Rails implementation was introduced in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/16018, and
acceptance testing was done in
https://gitlab.com/gitlab-org/gitaly/issues/881

Part of https://gitlab.com/gitlab-org/gitaly/issues/817

Revert "Merge branch '5480-sidebar-subscription-event-handling' into 'master'"

Closes #45979

See merge request gitlab-org/gitlab-ce!18692

Remove old GitLab Shell namespace actions implementations

See merge request gitlab-org/gitlab-ce!18681

Deprecation of ActionView's time_ago_in_words

Closes #45761

See merge request gitlab-org/gitlab-ce!18607

Increase new issue metadata form margin

Closes #44134

See merge request gitlab-org/gitlab-ce!18630

Save and expose only generic merge error

See merge request gitlab-org/gitlab-ce!18646