- rewrite add_UE_to_list() and rewrite remove_UE_from_list() to simplify
list handling
- return pointer from get_new_nr_ue_inst(); it's completely freed by
delete_nr_ue_data()
- have add_new_UE_RA() add UE context to access list; remove with
nr_release_ra_UE()
- have add_connected_nr_ue() only add UE to connected list; to move from
access to connected use transition_ra_connected_nr_ue(); remove with
mac_remove_nr_ue() as previously
- free memory on problems during RA
- add some documentation
- in NSA/HO: check for pre-configured RA process
- there are asserts in all functions to clarify when a UE has RA