Put fallback reply-key address first in the References header

See merge request gitlab-org/gitlab-ce!20871

Stop building Route rows on the fly

See merge request gitlab-org/gitlab-ce!20313

The References header is an ordered list of mails, and some clients
only look at the last mail in the list to determine to which mail the
mail is in reply to.

Therefore, to be a less obtrusive as possible, put the fallback
address first.

Some info about the reply key lookup in the References header:
https://docs.gitlab.com/ee/administration/reply_by_email.html#how-it-works

This reverts merge request !20679

Resolve "Making instance-wide data tools more accessible"

Closes #41416 and #48507

See merge request gitlab-org/gitlab-ce!20679

CE: Add PolicyCheckable concern for things passing to policy check

See merge request gitlab-org/gitlab-ce!20839

if all methods are also presented in the user.

Resolve "The comparison list for the modified icons"

Closes #48567

See merge request gitlab-org/gitlab-ce!20501

More Gitaly cleanup: fetch_ref, allow disk access blocks

Closes gitaly#1295

See merge request gitlab-org/gitlab-ce!20802

Rails5 update Gemfile.rails5.lock

See merge request gitlab-org/gitlab-ce!20858

[master] Escapes milestone title shown in flash message when promoting a milestone

See merge request gitlab/gitlabhq!2436

[master] Fixed XSS in branch name in Web IDE

See merge request gitlab/gitlabhq!2431

[master] Escapes job name used in tooltips

See merge request gitlab/gitlabhq!2427

[master] Missing CSRF in System Hooks

See merge request gitlab/gitlabhq!2419

Fix namespace move callback behavior, especially to fix Geo replication of namespace moves during certain exceptions

Closes gitlab-ee#6252

See merge request gitlab-org/gitlab-ce!19297

Fix namespace move callback behavior, especially to fix Geo replication of namespace moves during certain exceptions

Resolve "BS4: Link in code brackets has two different styles"

Closes #48542

See merge request gitlab-org/gitlab-ce!20841

Full list of vulnerabilities

See merge request gitlab-org/gitlab-ce!20855

Remove CSS

See merge request gitlab-org/gitlab-ce!20845

Update the image for the 'danger-review' job

See merge request gitlab-org/gitlab-ce!20856