Ambient-toolbox

* Fixed a bug in `BaseEmailService` where txt part was rendered sometimes with weird line breaks
* Added Bugtracker link to `setup.py`

* Translation files were missing in wheel
* Bugfix in docs

* Changed all translatable texts to English base version
* Added German translation file for current translatable
* Updated RequestProviderMixin.get_request() type hinting
* Added documentation for database anonymisation / django-scrubber wrapper

* Extended email attachment functionality to be able to define filename and mimetype

* *Breaking change:* Fixed typo in `WhitelistEmailBackend.whitify_mail_adresses` method name. Method is now
called `whitify_mail_addresses`
* Moved assignment of `WhitelistEmailBackend` settings var to static methods to be able to overwrite them if needed
* Added documentation about `WhitelistEmailBackend`
* Added some type hinting to `WhitelistEmailBackend`
* Added formset mixin `CountChildrenFormsetMixin`
* Added djangorestframework field `RecursiveField`
* Added `get_attachments()` method to `BaseEmailService` and extended constructor to accept a
variable `attachment_list`

* *Breaking change:* Moved `ReadOnlyAdmin` and `EditableOnlyAdmin` to package `model_admins.classes`
and `ReadOnlyTabularInline` to package `model_admins.inlines` to enable better structuring of new admin components
* Fixed some inconsistencies within `ReadOnlyAdmin`, `EditableOnlyAdmin` and `ReadOnlyTabularInline` classes
* Added `admin.views` package containing a base crispy form, and a mixin to turn any regular django view into a nice
and cozy django admin view
* Added an abundance of `model_admins.mixins`: `AdminCreateFormMixin`, `AdminNoInlinesForCreateMixin`
,`AdminRequestInFormMixin`, `FetchParentObjectInlineMixin`, `FetchObjectMixin`, `CommonInfoAdminMixin`
* Added `RequestProviderMixin` to easily create a dummy request in unittests
* Added support for django 3.2 and dropped support for 2.0, 2.1 and 3.0
* Added support for Python 3.9 and dropped support for 3.5
* Updated test python version to 3.9