Prepare 10.8 RC4 release

Main release issue: https://gitlab.com/gitlab-org/gitlab-ce/issues/45897

Summary

This MR prepares 10-8-stable for %10.8 (RC4) by merging 10-8-stable-prepare-rc4 into 10-8-stable.

Steps

1. Merge master into this branch
2. If there are any conflicts while picking MRs then attempt to resolve them; otherwise, create a new MR against the <%= preparation_branch_name %> branch and assign it to the author of the conflicting files.
3. Merge CE-to-EE using one of the workflows described in the Merge CE stable changes to EE docs

• Note: Often, after a release has been tagged, the VERSION file in ee will have a conflict. Accept the -ee one

1. Once this MR is green merge it to stable, preferably with a manual fast-forward merge to minimize waiting time, as described in Merging preparation MRs into stable

Picks:

• https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/18804

Checklist

7th 17:00 UTC

• Merge master into this branch

8th 6:59 UTC

• Merge master into this branch

• Conflicts resolved
• No new commits have introduced directly to the stable branch while this MR was in progress. If there are,<% unless ee? %> ensure these are merged into EE and<% end %> check for a green pipeline after merging this MR.