* remove duplicate context generation
* allow text templates in frontpage_text
* refactor: move placeholder functionality to separate file
* fix wrong class name, code style
* update year in license header
* undo license header update
* use new function name
* render only the placeholders that are actually used in the message
* refactoring
* add str(...) call
* Update doc/development/api/placeholder.rst
Co-authored-by: Raphael Michel <michel@rami.io>
* rename register_mail_placeholders to register_template_placeholders
(deprecate old name)
* isort
* add signals to docs
---------
Co-authored-by: Raphael Michel <michel@rami.io>
