This is functionality that isn't accessible via the user interface. The
API allows the creation and modification of an override template that
holds rules that needs to be checked when overriding the asset.
The API is setup that it cannot be changed after creation. Later on when
the system is more mature we will allow changing overrides operations.
NOTE: This is an experimental feature and should not be used in productions.
Reviewed By: mont29, sebbas
Differential Revision: https://developer.blender.org/D10792
Added a first test case for review. This will be the base for future test cases.
The current API is sufficient for what is expected for such a low level API.
One concern is that you need to trigger a save in order to update the library overrides
structure. Not expected from TD/Dev point of view.
Test cases are very important when implementing restrictive mode as it is a second evaluation mode that
has impact on the (current) permissive mode.
Reviewed By: Sebastián Barschkis, Bastien Montagne
Differential Revision: https://developer.blender.org/D10747
