Docs: groups page updates

See merge request gitlab-org/gitlab-ee!9754

Add developer documentation for distributing tracing

See merge request gitlab-org/gitlab-ce!25150

This change adds developer documentation on using distributed tracing
using Jaeger.

Adhere to stylelint specs

See merge request gitlab-org/gitlab-ce!25620

More Stylelint rules

See merge request gitlab-org/gitlab-ce!25266

EE-Port More Stylelint rules

See merge request gitlab-org/gitlab-ee!9747

EE Specific CSS Fixes

Removed an extraneous whitespace

Fixed single quotes in notes.scss

Feature: Runner tag filter for admin view

See merge request gitlab-org/gitlab-ce!19740

Port of feature/runner-tag-filter-for-admin-view to EE

See merge request gitlab-org/gitlab-ee!9658

Due to performance reasons we cannot use the type filter on the tags.
The table for ActsAsTaggableOn is too big and too unoptimized, such that
the queries time out on production.

See the discussion
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/19740#note_120087938
for more info.

The query generated by ActsAsTaggableOn `@taggable_type.all_tags` is
very inefficient (joins too much, grouping, inner select, ...).

the potential number of available runner tags is too large to load it
statically to a dropdown. we use the same lazy loaded dropdown as is
used for the users dropdown already.

Danger ignores gitlab.pot

See merge request gitlab-org/gitlab-ce!25594

Moved EE code out of CE members JS file

Closes #10019

See merge request gitlab-org/gitlab-ee!9743

CE backport of members-ee-code

See merge request gitlab-org/gitlab-ce!25593

Fix misspellings in app/spec executable lines

See merge request gitlab-org/gitlab-ce!25521

EE port: Fix misspellings in app/spec executable lines

See merge request gitlab-org/gitlab-ee!9690

Fixed placeholder text in feature proposal issue template

See merge request gitlab-org/gitlab-ee!9748

Fixed placeholder text in feature proposal issue template

See merge request gitlab-org/gitlab-ce!25603

Add reordering of child epics

See merge request gitlab-org/gitlab-ee!9283