backwards migration for messages via API
Revert "backend models for messages"

This reverts commit 261ef2691431aa7b260c657d6a533c76fcf7797d.

Conflicts:
	famille/models/messages.py
	famille/tests/test_models.py
Revert "API for messages"

This reverts commit 7b9d59f5019e197b6afdd12deeab58eb3198a4fa.

Conflicts:
	famille/models/messages.py
	famille/tests/test_models.py