CE upstream: thursday

Closes gitlab-qa#73, #3611, gitaly#585, gitlab-ce#38417, gitlab-ce#38743, gitlab-ce#38315, gitlab-ce#38187 et gitlab-design#35

See merge request gitlab-org/gitlab-ee!3072

Fix Geo transfers failure handling when filename too long

Closes #3682

See merge request gitlab-org/gitlab-ee!3095

Improved Geo development documentation with 10.0 and 10.1 changes.

See merge request gitlab-org/gitlab-ee!2978

Remove executable permissions on images to make docs lint happy

See merge request gitlab-org/gitlab-ee!3094

Improves existing log information as well.

Closes #3682

Normalize LDAP user DNs (downcase and remove excess spaces)

Closes #3151

See merge request gitlab-org/gitlab-ee!2942

EE-port:  Create merge requests across a fork network

See merge request gitlab-org/gitlab-ee!3087

[ci skip]

Port to EE "Bump google-api-client Gem from 0.8.6 to 0.13.6"

See merge request gitlab-org/gitlab-ee!3084

Fix personal snippet attachments not downloading in Geo secondaries

Closes #3644

See merge request gitlab-org/gitlab-ee!3091

So we can keep showing it to a user in his project page.

This uses the existing ForkedProjectLinks

The helper creates a fork of a project with all provided attributes,
but skipping the creation of the repository on disk.

When no fork network exists for the source projects, we create a new
one with the correct source

The fork network will keep track of the root project as long as it's
present.

Closes #3644

The CE->EE merge renamed `RepoLicense` to `License`. It's easier to rename
the EE-only code than to try to sort it out.

Schedules repository sync when handling events in the Geo Log Cursor

Closes #3230

See merge request gitlab-org/gitlab-ee!2838

Fix "verify_certificates" config key name in docs

See merge request gitlab-org/gitlab-ee!3085

Create idea of read-only database

Closes #2855, #3398, #3399, and #3505

See merge request gitlab-org/gitlab-ee!2954

Merge branch '38771-skip-fork-mirror-and-import-start-if-the-worker-was-reset-without-cleanup' into 'master'

Import/Fork/Mirror jobs now skip starting transition if the worker was killed…

See merge request gitlab-org/gitlab-ee!3071