Add new motion restriction modes

[jsangmeister]

see OpenSlides/openslides-backend#2119:

• The new motion restriction mode B should only be visible to users with motion.can_manage

see OpenSlides/openslides-backend#2120:

• TODO

[jsangmeister]

For OpenSlides/openslides-backend#2120, we still need to decide on how to exactly model it. A possible way could be to implement this in the restricter the following way: To determine if the user can see the field motion/recommendation_id, the restricter follow the relation and checks the field motion_state/internal_recommendation. If that is true, the user needs motion.can_manage to see the recommendation. Otherwise, restriction mode C is used. @ostcar will evaluate how feasible this solution is or if there is a better way to model it.

[jsangmeister]

extracted second bullet point to #840. Closing this.