The next commit implements the release of all UEs following the F1 Reset
message. It uses nr_mac_release_ue(), which as of now, triggered a
release complete message automatically, which we don't want in the case
of F1 Reset.

This commit refactors the code to split UE release at MAC/RLC and
release complete message sending to allow to release UEs without sending
the complete. Corresponding users are updated.