This adds a method to Gitlab::GonHelper called
`push_frontend_feature_flag`. This method can be used to easily expose
the state of a feature flag to Javascript code. For example, using this
method we may write the following controller code:

    before_action do
      push_frontend_feature_flag(:vim_bindings)
    end

    def index
      # ...
    end

    def edit
      # ...
    end

In Javascript we can then check the state of the flag as follows:

    if ( gon.features.vimBindings ) {
      // ...
    }

Fixes https://gitlab.com/gitlab-org/release/framework/issues/17

Replace old "secret variables" image for variables with new "variables" image

See merge request gitlab-org/gitlab-ce!22184

Redirect to the pipeline builds page when a build is canceled

Closes #39161

See merge request gitlab-org/gitlab-ce!21595

Resolve "Merge request buttons spacing incorrect"

Closes #48494

See merge request gitlab-org/gitlab-ce!22135

Docs - Prefilled fields for new issue link

See merge request gitlab-org/gitlab-ce!22082

Added note to clarify values for hook-name.d

See merge request gitlab-org/gitlab-ce!22165

Improve QA page README

See merge request gitlab-org/gitlab-ce!22176

Update explanation about the `extends` feature

See merge request gitlab-org/gitlab-ce!22043

Add note about hostname *and* port needing to match for `DOCKER_AUTH_CONFIG`

See merge request gitlab-org/gitlab-ce!22064

Fix link to EE-only doc and fix lint issues

See merge request gitlab-org/gitlab-ce!22178

Fix link to MR-template and other improvements

See merge request gitlab-org/gitlab-ce!22179

Fix indentation in GPG documentation

See merge request gitlab-org/gitlab-ce!22132

Enable more frozen string in lib/**/*.rb

See merge request gitlab-org/gitlab-ce!22174

Rails 5: fix mysql milliseconds problems in scheduled build specs

See merge request gitlab-org/gitlab-ce!22170

Update templates for 11.4

See merge request gitlab-org/gitlab-ce!22188

Prune events older than 2 years instead of 12 months

See merge request gitlab-org/gitlab-ce!22145

Remove duplicate Sentry logging for GRPC exceptions

See merge request gitlab-org/gitlab-ce!22187

Update licenses for 11.4

See merge request gitlab-org/gitlab-ce!22189

Fix issues controller N+1 failure

See merge request gitlab-org/gitlab-ce!22141

Updates Laravel.gitlab-ci.yml template

See merge request gitlab-org/gitlab-ce!22167

Render log artifact files in GitLab

See merge request gitlab-org/gitlab-ce!22112

Raven.capture_exception is already called by log_exception.

We can infer from the given examples but it is implicit.

We have an explanation for `explain` (by way of examples) but nothing to
say what view does.

Enables frozen for the following:

* lib/*.rb
* lib/banzai/**/*.rb
* lib/bitbucket/**/*.rb
* lib/constraints/**/*.rb
* lib/container_registry/**/*.rb
* lib/declarative_policy/**/*.rb

Partially addresses #47424.

Check disabled_services when finding a service

See merge request gitlab-org/gitlab-ce!22172

Fix invalid parent path on group settings page

Closes #52242

See merge request gitlab-org/gitlab-ce!22142

Backport CE changes for: [Frontend only] Batch comments on merge requests

See merge request gitlab-org/gitlab-ce!22158