Made modwsgi groups_for_user consistent with check_password

2b5f848207b1dab35afd6f63d0107629c76d4d9a based its changes on #19061
that made the is_active attribute mandatory for user models.
The try/except was not removed for the groups_for_user function.

refs #19780
Fixed #19707 -- Reset transaction state after requests
Fixed #19638 -- Skipped tx support testing for some DBs

PostgreSQL and Oracle always support transactions, so the create table
and rollback test is non-necessary on those DBs.

Thanks to shai for report.
Fixed #19720 -- Oracle ordering related delete regression

When a query had a complex where condition (a condition targeting more
than the base table) a subquery was used for deletion. However, the
query had default ordering from the model's meta and Oracle doesn't
work with ordered subqueries.

The regression was caused by fast-path deletion code introduced in
1cd6e04cd4f768bcd4385b75de433d497d938f82 for fixing #18676.

Thanks to Dylan Klomparens for the report.
Added a note about the default timezone and the new project template.

Thanks JonLoy for the draft patch.
Made Query.clear_ordering force_empty arg mandatory

Previously it was possible to call clear_ordering without the
force_empty argument. The result was that the query was still ordered
by model's meta ordering if that was defined. By making the arg
mandatory it will be easier to spot possible errors caused by assuming
clear_ordering will remove all ordering.

Thanks to Dylan Klomparens for the suggestion. Refs #19720.
Fixed #19112 -- Reduced the amount of query params in a test
Emphasized MyISAM pseudo-requirement for GeoDjango over MySQL

Refs #15295.
Updated tutorial 1 to reflect changes in default project template.

Thanks JonLoy for the patch.
Fixed #19044 -- Made `DeletionMixin` interpolate its `success_url`.

Thanks to nxvl and slurms for the initial patch, ptone for the review
and timo for the documentation tweaks.
Added a check in the creation of IS NULL clauses.

value_annotation isn't very well defined. Before this change, setting it
to datetime.datetime could silently reverse the behavior of isnull
lookups. This commit doesn't have any consequences on the current code.
It's just a safeguard for future ORM hackers.
Accepted None in tzname().

This is required by the tzinfo API, see Python's docs.

Also made _get_timezone_name deterministic.
Mention backward relationships in aggregate docs.

Thanks Anssi and Marc Tamlyn for reviewing.

Fixes #19803.
Fixed #19808 Capitalization error in example text
Merge pull request #719 from JonLoy/ticket_19808

Fixed #19808 -- Typo in example
Removed try-except in django.db.close_connection()

The reason was that the except clause needed to remove a connection
from the django.db.connections dict, but other parts of Django do not
expect this to happen. In addition the except clause was silently
swallowing the exception messages.

Refs #19707, special thanks to Carl Meyer for pointing out that this
approach should be taken.
Fix admindocs on Python 3, where None cannot be sorted with strings.

This fixes two tests in admin_views which were failing on Python 3, but only if
the tests were run with docutils installed.
Fixed #18558 -- Added url property to HttpResponseRedirect*

Thanks coolRR for the report.
Fixed #19693 -- Made truncatewords_html handle self-closing tags

Thanks sneawo for the report and Jonathan Loy for the patch.
Fixed #8404 -- Isolated auth password-related tests from custom templates