Fixed tests broken in 2ee21d9.
Fixed #19929 -- Improved error when MySQL doesn't have TZ definitions.

Thanks tomas_00 for the report.
Created a helper type to handle the deprecation path when renaming
methods (i.e. Manager.get_query_set > Manager.get_queryset).
Refs #15363.
Normalized to `get_queryset` the name of methods that return a queryset.
Refs #15363.
Updated tests in regard to cdc024fd2820ee40bad088ea2f925e7b6223b02d.
Updated docs in regard to cdc024fd2820ee40bad088ea2f925e7b6223b02d.
Added myself to AUTHORS.
Added documentation for #15363.
Modified `RenameMethodsBase` to allow setting the deprecation warning
on a per method basis.