Fix sub-second timing comparison error for Devise confirmation period

Closes gitlab-ee#2362

See merge request !11156

Update gitignore, dockerfile, and license templates for 9.2

See merge request !11158

Add documentation about adding foreign keys

See merge request !11117

[ci skip]

Update the vendor licenses file for 9.2

See merge request !11159

clarify DB/Redis HA docs

See merge request !11094

New doc topic: issues

Closes #27650

See merge request !11075

Add confirm delete protected branch modal

Closes #21393

See merge request !11000

Omit gl_project_id from Import/Export

Closes #29813

See merge request !11032

On databases such as MySQL, it's possible to get into a timing comparison
error if the value of `Confirmable#confirmation_sent_at` is within a second
of `0.days.ago`. This is possible mostly in specs that test this behavior
and most likely not happening in practice. The result of this error causes
a user to be deemed active when it should be inactive. To prevent this
error, we explicitly check the configuration setting to be `0.days.ago`.

Closes gitlab-org/gitlab-ee#2362

Add support for commit diff ignore_whitespace_change and paths flags

Closes gitaly#198

See merge request !11028

Revert "Merge branch 'fix-rspec_profiling-establish_connection-string-deprecation' into 'master'"

See merge request !11153