Re-add Feature.register_feature_groups which is already documented
What does this MR do?
Re-add Feature.register_feature_groups which is already documented
This is a follow-up for !12362 (merged) where this was documented but the code was removed in the last iteration. Since this can still be useful and this is already supported by the API, I think re-adding the code was the best course of action.
Closes #34891 (closed)