Fix MergeRequest#has_commits? nil comparison

Closes #59547

See merge request gitlab-org/gitlab-ce!26828

Add # frozen_string_literal to spec/models

See merge request gitlab-org/gitlab-ce!26791

Dry up and remove responsibilities from services

Closes #58646

See merge request gitlab-org/gitlab-ce!26731

- Dry create_service.rb and update_service.rb duplicated code
- Remove known list of applications responsibility from services
- Refactor the complex builders->builder call from base_service.rb

Fix styleling for `app/assets/stylesheets/framework/markdown_area.scss`

See merge request gitlab-org/gitlab-ce!26768

Update lfs_administration.md to add new line in order to have table draw properly

See merge request gitlab-org/gitlab-ce!26827

Persist page and date range in Group Security Dashboard URL

Closes #9677

See merge request gitlab-org/gitlab-ee!10402

This follows straight-forwardly from [previous work][1] to persist some
state of the Group Security Dashboard to the URL, and vice versa.

[1]: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/9108

Documentation: added missing } in a json example

See merge request gitlab-org/gitlab-ee!10497

Display link to next to note in text email

See merge request gitlab-org/gitlab-ce!26695

Display link to each review note in text email

Closes #10220

See merge request gitlab-org/gitlab-ee!10401

Fix typo in QA auto_devops spec

See merge request gitlab-org/gitlab-ce!26809

Fix API /project/:id/branches not returning correct merge status

Closes #56250

See merge request gitlab-org/gitlab-ce!26785

Notify owner that group is invalid when LDAP "Sync now" fails

See merge request gitlab-org/gitlab-ee!10509

Fix ChatOps responder for gitlab.com

See merge request gitlab-org/gitlab-ee!10416

Added image component to design detail view

See merge request gitlab-org/gitlab-ee!10480

add a uniq constraints on issues and mrs labels

See merge request gitlab-org/gitlab-ce!25435

Remove dead code

See merge request gitlab-org/gitlab-ee!10493

Add no-op license helper to CE

See merge request gitlab-org/gitlab-ce!26723

Port Add no-op license helper to CE

See merge request gitlab-org/gitlab-ee!10485

[CE] - Load 'Gitlab::Jira::Middleware' if it exists

See merge request gitlab-org/gitlab-ce!26665

Loads 'Gitlab::Jira::Middleware' only if it exists
so this initializer can be backported to CE.

Load Gitlab::Jira::Middleware only if it exists

Closes #10672

See merge request gitlab-org/gitlab-ee!10459

Loads 'Gitlab::Jira::Middleware' only if it exists
so this initializer can be backported to CE.

Clarify that personal access token should be sent as password for authentication.

See merge request gitlab-org/gitlab-ce!22603