- many structs and definitions are overlapping between the two different E1 procedures
- introduced naming specific to E1 Bearer Context Modification to improve readability
- grouped SDAP and PDCP configuration IEs for better reusability and readability
- introduced functions to set and get default PDCP config (DRBs and Bearer Contexts)

find_or_next_pdu_session:
- find_or_next_pdu_session refers to the E1 Bearer Context Modification Request
-- therefore it has to return pdu_session_to_mod_t* and takes in input e1ap_bearer_mod_req_t *

see !MR2545 for more context