Remove project_mirror_data created_at and updated_at columns

Closes gitlab-qa#237

See merge request gitlab-org/gitlab-ee!5629

# Conflicts:
#   db/schema.rb

Simplify Geo doc wording

See merge request gitlab-org/gitlab-ee!5618

Don't add project_mirror_data columns that have already been added

Closes #5939

See merge request gitlab-org/gitlab-ee!5628

Adjust spec to build correct path when storage path ends in slash

See merge request gitlab-org/gitlab-ee!5632

CE upstream - 2018-05-08 21:28 UTC

See merge request gitlab-org/gitlab-ee!5620

Docs: add custom descriptions to most relevant docs

See merge request gitlab-org/gitlab-ee!5603

Stop presenting burndown charts promotion for grouped milestones

Closes gitlab-ce#46129

See merge request gitlab-org/gitlab-ee!5616

In !5586, some `add_column` statements were moved between migrations.
If the original migrations were already run on a user's instance,
the new migrations would try to add the columns again.

(cherry picked from commit 7b8d754e)

Correct grammar in Use-cases section of Repository Mirroring docs

See merge request gitlab-org/gitlab-ee!5584

# Conflicts:
#	app/models/project.rb
#	app/presenters/ci/pipeline_presenter.rb
#	app/views/projects/pipelines/_with_tabs.html.haml

[ci skip]

Raise InvalidRepository error for non-valid git repositories

See merge request gitlab-org/gitlab-ce!18594

Add missing parens to make consistent in project_spec and runner_spec

See merge request gitlab-org/gitlab-ce!18808

Resolve "Geo: Gitlab::Git::CommandError (13:exit status 128) when calculating checksums"

Closes #5750

See merge request gitlab-org/gitlab-ee!5486

CE upstream - 2018-05-08 00:16 UTC

Closes #5904, #5573, and #5857

See merge request gitlab-org/gitlab-ee!5608

There are two issues:

1. When a Wiki was disabled, the spec was still trying to create a
Wiki page, which would cause Gitaly to create the repository and fire
hooks. Since Rails isn't running an internal API server, this fails.

2. For private Wikis, the Wiki repository needs to be created with the
:wiki_repo trait in order to clear hooks to prevent Gitaly from
contacting the internal API server.

Update asset_sync ~> 2.2.0 to ~> 2.4

See merge request gitlab-org/gitlab-ce!18762

Cleanly handle plural name for ghost user migration

See merge request gitlab-org/gitlab-ce!18798

Merge branch '5926-getting-geo-secondary-database-is-not-configured-when-only-running-ee-sha_attribute' into 'master'

Getting "Geo secondary database is not configured" when only running EE (sha_attribute)

Closes #5926

See merge request gitlab-org/gitlab-ee!5614

Trying to present burndown charts promotion generated
https://gitlab.com/gitlab-org/gitlab-ce/issues/46129. We're now making
sure we're not presenting the promotion for grouped by title milestones.

Add database foreign key between pipelines and builds

Closes #46035

See merge request gitlab-org/gitlab-ce!18822

Squash migrations from 2013

See merge request gitlab-org/gitlab-ee!5464