CE upstream: Thursday

Closes gitlab-ce#29192, #1381, and gitlab-com/infrastructure#1139

See merge request !1398

which isn't properly cleaning up whenever something
is thrown, not raised. See:

https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1402#note_25128108

Fix 500 when selecting a mirror user

Closes gitlab-ce#29316

See merge request !1404

Add detailed explanation of merge options

Closes #257

See merge request !1350

When selecting a mirror user, we do a permissions check, which means
that `@users` is an array, not an ActiveRecord relation.

We also can't use `Array#delete`, because it uses `Object#equal?`, while
we need to be able to take advantage of ActiveRecord objects overriding
`#eql?` and `#hash?` (as `Array#uniq` uses a hash internally).

Add update doc for CE 9.0 to EE 9.0

See merge request !1394

Update storage settings to allow extra values per shard

See merge request !1362

Add Upload count to usage data

See merge request !1401

Fix Projects::UpdateService#repository_storage spec to take account of schema changes in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/9597

Fix the #change_repository_storage tests to take account of schema changes in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/9597

Improve storage validation after configuration structure update

See merge request !9811

Verbosify blocked pipeline status description

Closes #29134

See merge request !9800

Change activity view wording

See merge request !9777

CE upstream

Closes gitaly#109 and gitlab-ce#28515

See merge request !1371

Move u2f javascript library to webpack config

See merge request !9755

Fix wrong message on starred projects filtering

Closes #28402

See merge request !9488

Update the gitignore and gitlab-ci templates for 9.0

See merge request !9824

# Conflicts:
#   doc/api/v3_to_v4.md

Remove timeout from awards_handler_spec.js

See merge request !9822

Signed-off-by: Rémy Coutable <remy@rymai.me>

Port of 1381-present-commits-pagination-headers-correctly to EE

See merge request !1357

specify where to finish database HA setup

See merge request !9731

Fixed typo with project service documentation link

See merge request !9708