Add release notes for Review Board 4.0.10.

Review Request #39 — Created Aug. 3, 2022 and updated — Latest diff uploaded

Review Board
This is a re-release of 4.0.8 and 4.0.9. Both those releases had
packaging issues. 4.0.8 had a bad dependency and broken merge, and both
releases had a packaging issue triggered by changes in Babel.

This re-release fixes the remaining known issues.

The 4.0.8 and 4.0.9 releases have been officially pulled from PyPI, and
the release notes here have been updated to simply point to the 4.0.10
release notes instead.

Testing Done:
Built the docs. Checked for bad links and build errors.

Checked the links from the 4.0.8 and 4.0.9 release notes to 4.0.10.

Reviewed at