[1.7.x] Fixed #23446 -- Officially recommended mysqlclient as MySQL driver

Thanks Corey Farwell for the report and Tim Graham for the review.
Thanks also to Inada Naoki for creating and maintaining mysqlclient.
Backport of 7f089ac2e3 from master.
[1.7.x] Fixed documentation of make_password kwargs.

Backport of ed7c4df1ee from master
[1.7.x] Fixed #23699 -- Prevented flush from loading initial data for apps with migrations.

Backport of dd1ea70779 from master.
[1.7.x] Edited release note for refs #23621.
[1.7.x] Fixed flake8 warning.

Backport of ef9e3c5ed8 from master
[1.7.x] Fixed stable/1.7.x test failures from refs #23699.
[1.7.x] Fixed #23717 -- Fixed makemessages crash when STATIC_ROOT=None

Backport of 528c9af54 from master.
[1.7.x] Fixed typo in MySQL backend doctring

Thanks CHI Cheng for the report.
[1.7.x] Added GeoDjango compatibility with mysqlclient driver

Thanks Tim Graham for helping on that issue.
[1.7.x] Fixed typo in squashing migrations documentation

Backport of af7d66b4f2 from master
[1.7.x] Fixed #23708 -- Corrected mod_wsgi docs reference to nonexistent comment in wsgi.py.

Thanks inglesp for the report.

Backport of e460b1c573 from master
[1.7.x] Fixed QuerySet datetimes argument name in docs.

Backport of 6b39401baf from master