Django-admin-sortable2

- Fix [\302](https://github.com/jrief/django-admin-sortable2/issues/302):
Django's ManifestStaticFilesStorage references missing file `adminsortable2.js.map`.

- Drop support for Django 3.2 and lower.
- Replace jQuery-UI's [sortable](https://jqueryui.com/sortable/) against
[Sortable.js](https://sortablejs.github.io/Sortable/).
- Use TypeScript instead of JavaScript for all client side code.
- Remove all extended Django admin templates: This allows a smoother upgrade
for future Django versions.
- New feature: Select multiple rows and drag them to a new position.

- Fix [\294](https://github.com/jrief/django-admin-sortable2/issues/294):
issue in 1.0.3 where `install_requires` unintentionally dropped Django 2.2

- Adding support for Django 4 and Python 3.10.

- Fix regression introduced in 1.0.1, adding double item rows on
SortableInlineAdminMixin and TabularInline.

- Fix CSS classes change introduced in Django-2.1.
- Prepared to run on Django-4.0.
- Ditch Travis-CI in favor of GitHub Actions.