Improve error messaging across various IDE actions

See merge request gitlab-org/gitlab-ce!20241

Add pipeline stages position clean-up migration

Closes #45956

See merge request gitlab-org/gitlab-ce!19369

Add transfer project endpoint to the Projects API

Closes #45146

See merge request gitlab-org/gitlab-ce!20122

Fix ambiguous due_date column for Issue scopes

Closes #47769

See merge request gitlab-org/gitlab-ce!20251

Always serve favicon from main GitLab domain so that CI badge can be drawn over it

Closes #47802

See merge request gitlab-org/gitlab-ce!20263

Enabling Doorkeeper reuse_access_token option

Closes #46278

See merge request gitlab-org/gitlab-ce!20200

Rails5 fix MySQL milliseconds problem in specs

Closes #48430

See merge request gitlab-org/gitlab-ce!20221

Rails5 fix Mysql comparison failure caused by milliseconds problem

Closes #48432

See merge request gitlab-org/gitlab-ce!20222

in this it also removes Vue Resource from the IDE, axios is nicer to test

Merge branch '43472-remove-environment-scope-field-on-cluster-creation-form-for-core-starter-plans' into 'master'

Resolve "Remove "environment scope" field on cluster creation form for core/starter plans"

Closes #43472

See merge request gitlab-org/gitlab-ce!19643

Fix OAuth application authorization screen to appear with every access

See merge request gitlab-org/gitlab-ce!20216

Prettifies pipeline's javascript code

See merge request gitlab-org/gitlab-ce!20217

Prevent fetching diffs and discussions data unnecessarily on MR page

Closes #48493

See merge request gitlab-org/gitlab-ce!20190

Schedule workers to delete non-latest diffs in post-migration

See merge request gitlab-org/gitlab-ce!20013

Keep label on issue when moving

Closes #46098

See merge request gitlab-org/gitlab-ce!20036

Add how to manage a regression

See merge request gitlab-org/gitlab-ce!17530

Resolve "SQL Queries are not shown from the Performance Bar in Safari"

Closes #48515

See merge request gitlab-org/gitlab-ce!20233

Resolve "Sidebar on jobs and wikis is missing at small widths"

Closes #48471

See merge request gitlab-org/gitlab-ce!20188

Resolve "Markdown header `code` does not have the correct font-size"

Closes #48549

See merge request gitlab-org/gitlab-ce!20229

Add note to README about using $CI_COMMIT_REF_SLUG when using forward-slashes

See merge request gitlab-org/gitlab-ce!20209

Fix paragraph line height for emoji

Closes #48003

See merge request gitlab-org/gitlab-ce!20137