babel extractors are now registered via python entry points,
so there is no need to declare babel extractors in babel configs.
This change is important to make translation work in Django 2.2.
django-babel does not work with Django 2.2 and looks unmaintained
for over two years. The horizon team is thinking to switch the extractor
to enmerkar (a fork of django-babel) to make extraction of translation
string work again near future. It is important to drop the extractor
definition to make the transition smooth.
Change-Id: I24d333db823232f9d7a86f474a94c95d68b3b07b
Currently strings in Django templates cannot be translated
because the current recommended file pattern "templates/**.html"
does not match Django templates in subdirectories.
This needs to be "**/templates/**.html".
Change-Id: I11bf9397c7feea0ec3c7fef9a94963fe1c38010b
Closes-Bug: #1747453