+ Dynamic trees: add 'dynamic_attrs' parameter support for item() (cl…

…oses #313).

+ Dynamic trees: add support for user-defined tree item access checks (closes #314).
* Add missing migrations, check them during testing.
* Add QA for Python 3.11 and Django 5.0. Dropped QA for Python 3.6

* Defined 'default_auto_field' in 'SiteTreeConfig'.

* Fixed LazyTitle issues in Django 4.

* Django 4.0 compatibility improved.

+ Add 'extra_class_ul' variable to Bootstrap and Foundation templates.

+ Add Bootstrap 5 templates.
* Fixed 'sitetreedump' command (see #295).
* Fixed app config handling in INSTALLED_APPS (see #292).
* Permissions in dynamic item are now lazy evaluated (see #302).

+ Introduced 'SITETREE_CACHE_NAME' setting.

* Fixed tree item resolution for URLs having special chars (see #288).
* Improved URL resolution performance.

* Made Django 3.1 compatible.

* Fix regression preventing LazyTitle to be restored from cache.

! Dropped support for Django<2.0.

! Dropped support for Python 2 and 3.5.
* Updated German translation.

+ Add Django 3.0 compatibility. Effectively deprecates Py2 support.