Reduce Bundle Size by making select2 loading optional

Closes #56988

See merge request gitlab-org/gitlab-ce!24727

EE Port for lazy loading select2

See merge request gitlab-org/gitlab-ee!9353

Fix metrics graphs environments dropdown

Closes #49388

See merge request gitlab-org/gitlab-ce!24441

Make refactored Epic app as default

Closes #7753 and #7751

See merge request gitlab-org/gitlab-ee!9361

Add git credentials to .netrc when needed

Closes gitlab-org/quality/nightly#57 and #56857

See merge request gitlab-org/gitlab-ce!24691

Resolve "Add Avatar from author of the last commit to WebIDE status bar"

Closes #46111

See merge request gitlab-org/gitlab-ce!24785

Wraps all imports for select 2 to deferred imports,
especially in the main.js we are actually checking if there 
is any select 2 element on the page or not.

Use ee_else_ce alias to resolve merge request widget files

See merge request gitlab-org/gitlab-ce!24374

Use ee_else_ce alias to resolve merge request widget files (EE-port)

See merge request gitlab-org/gitlab-ee!8135

EE Port: Docs: Change non-standard NBSP space to regular SP space

See merge request gitlab-org/gitlab-ee!9356

Docs: Change non-standard NBSP space to regular SP space

See merge request gitlab-org/gitlab-ce!24794

Update web terminal note for shared runners

See merge request gitlab-org/gitlab-ce!24754

Highlight when CI_ENVIRONMENT_* environment args are present

See merge request gitlab-org/gitlab-ce!24484

Fix CSS grid on a new Project/Group Milestone

Closes #56764

See merge request gitlab-org/gitlab-ce!24614

This reverts merge request !24485

Split epic label dropdown test cases in gfm_autocomplete_spec.rb

Closes #9456

See merge request gitlab-org/gitlab-ee!9330

fix display comment avatars issue in IE 11

Closes #56931

See merge request gitlab-org/gitlab-ce!24777

There was a bug that required credentials when using SSH key auth when
using LFS. That bug was fixed so we shouldn't need to add credentials to
.netrc when using SSH anymore.

Create security release MR template

Closes gitlab-org/release/framework#168, gitlab-org/release/framework#166, and gitlab-org/release/framework#167

See merge request gitlab-org/gitlab-ce!24725

Remove all the code and references to old Epic app.

Use refactored Vuex Epic app in place of older Epic app.