This is the EE-port of 5ea377a4

# Conflicts:
#	Gemfile.lock
#	Gemfile.rails5.lock
#	app/assets/javascripts/boards/components/issue_card_inner.vue
#	app/assets/javascripts/environments/components/environment_item.vue

[ci skip]

CE upstream - 2018-10-15 17:21 UTC

Closes gitlab-ce#39697

See merge request gitlab-org/gitlab-ee!7938

Fixes styling issues in test reports

Closes #51386 and #52147

See merge request gitlab-org/gitlab-ce!22204

Resolve "Project slug does not auto populate in IE11"

Closes #52686

See merge request gitlab-org/gitlab-ce!22367

Verify that usage ping works when all counts time out

See merge request gitlab-org/gitlab-ce!22358

Verify that usage ping works when all counts time out

See merge request gitlab-org/gitlab-ee!7926

[QA] Handle sign-up when terms must be accepted

See merge request gitlab-org/gitlab-ce!22374

Use grpc v1.15.x

See merge request gitlab-org/gitlab-ee!7939

Add IID headers to E-Mail notifications

Closes #52477

See merge request gitlab-org/gitlab-ce!22263

Merge branch 'ee-49417-improve-settings-pages-design-by-prioritizing-content-group-settings' into 'master'

EE port gitlab-ce!21115

See merge request gitlab-org/gitlab-ee!7720

Fixed file templates not clearing in Web IDE

Closes #52487

See merge request gitlab-org/gitlab-ce!22357

Document linguist overriding

See merge request gitlab-org/gitlab-ce!22386

Fixes diff stats not being visible with performance bar

See merge request gitlab-org/gitlab-ce!22390

Disable artifact validation for download action

See merge request gitlab-org/gitlab-ce!22300

Refactor test reports

See merge request gitlab-org/gitlab-ee!7827

Use grpc v1.15.x

See merge request gitlab-org/gitlab-ce!22350

These headers can be used to build URLs for API requests. Good examples
would be Issues and Merge Requests

Update git and install git-lfs QA docker image

See merge request gitlab-org/gitlab-ce!22355

Project::ClustersController spec improvement

See merge request gitlab-org/gitlab-ce!22346

Users report that some languages aren't detected, or at least not
reported. This is mostly due to the fact that these languages aren't
programming languages, according to Linguist.

Originally noted in: https://gitlab.com/gitlab-org/gitlab-ce/issues/50705#note_99600216

Related: https://gitlab.com/gitlab-org/gitlab-ce/issues/51995

Resolve "Prometheus not showing as installed, even though it is"

Closes #51972

See merge request gitlab-org/gitlab-ce!22356

Resolve "Prometheus not showing as installed, even though it is"

See merge request gitlab-org/gitlab-ee!7925

Create system notes for epic close and reopen

Closes #7015

See merge request gitlab-org/gitlab-ee!7850