Django-appmail

* Add support for Django 5.0
* Add Python 3.12 to classifiers and build matrix

* Improve LoggedMessage admin list page performance.
* Add support for Django 4.2
* Drop support for Python 3.8

Bump in version due to potential breaking change.

* [Potential breaking change] New indexes on the LoggedMessage model; take
care when applying this migration as your table may be large in size.
* Fix crash in admin logged messages when a related template has been deleted.
* Fix n+1 query issue in logged messages admin listing.

* Add support for Python 3.11.
* Drop support for Django 3.0, 3.1.

* Add Django 4.1 to build matrix.

* Add management command to truncate logs after a period.