When displaying a Group details page we check if epics are enabled for
the group and all of its descendants. For this set we will eventually
run at least one SQL query per Group to get the plans said Group has
access to. In case of a hierarchy with 20 groups this means at least 20
SQL queries.

In this commit we introduce Gitlab::GroupPlansPreloader. This is a
custom class that takes an ActiveRecord::Relation of Group objects and
efficiently preloads the plans for these groups. This class only needs
three SQL queries to do its work:

1. A SQL query to get the groups and all of their ancestors.
2. A SQL query to get all the plans all of these groups have access to.
3. A SQL query to get the groups to assign the plans to, then return to
   the caller.

Using this data the class can then determine which groups have access to
what plans.

Fixes https://gitlab.com/gitlab-org/gitlab-ee/issues/6206

Resolve "ee/spec/lib/gitlab/geo/oauth_session_spec.rb test doesn't actually do anything"

Closes #6111

See merge request gitlab-org/gitlab-ee!5896

Cleanup EE specific code for Project settings

See merge request gitlab-org/gitlab-ee!5902

Removal of API v3 from the codebase

See merge request gitlab-org/gitlab-ee!5839

Resolve "Revert to use a simpler check for `ee-files-location-check`"

Closes #6243

See merge request gitlab-org/gitlab-ee!5910

CE upstream - 2018-05-31 06:24 UTC

See merge request gitlab-org/gitlab-ee!5917

Add Wiki and Snippets to project feature overview

See merge request gitlab-org/gitlab-ce!19235

CE upstream - 2018-05-31 00:23 UTC

See merge request gitlab-org/gitlab-ee!5916

[ci skip]

# Conflicts:
#	CHANGELOG.md

[ci skip]

CE upstream - 2018-05-30 22:00 UTC

See merge request gitlab-org/gitlab-ee!5914

[ci skip]

[ci skip]

[ci skip]

[ci skip]

[ci skip]

Update "col-xs" usage to bootstrap4

Closes #47002

See merge request gitlab-org/gitlab-ce!19256

Make Repository#blob_data_at a public method

See merge request gitlab-org/gitlab-ce!19259

CE upstream - 2018-05-30 15:02 UTC

Closes #6045, #2678, and omnibus-gitlab#2138

See merge request gitlab-org/gitlab-ee!5906

Treat external authorization service response status 403 as failure

Closes #6235

See merge request gitlab-org/gitlab-ee!5909

Add missing usage_ping_enabled to API settings

See merge request gitlab-org/gitlab-ce!19263

Fix   after sign-in with Google button

Closes #45551

See merge request gitlab-org/gitlab-ce!19249

[ci skip]

[ci skip]

Fix bad merge causing duplicate methods in app/assets/javascripts/vue_merge_request_widget/components/states/ready_to_merge.vue

Identified while resolving conflicts in https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/5906