New `_populate_default` option for model creation, that if a model is created with a value for a non-default translation, copies the value as the default. Useful if you need to ensure that a fallback is always available, but don't want to fill anymore than necessary.
Let `_populate` and `_populate_default` be used with `get_or_create`. This unfortunately requires a second query due to Django internals.
Merge branch 'feature/populate-default-and-get-or-create' into develop