This reverts commit ffb6fa7c

This reverts commit f2074461

modify some issues
add f1ap ue context procedure

This commit contains work done by Eurecom and by Benetel.

When a header is changed, all including files need to be recompiled,
too. Thus, including a header needlessly all over the place drives
compile times up without any reason.

* Restructure the code handling the UEs F1AP knows
* This fixes a bug that only two phones can be connected

This commits isolates the S1 UE Ctxt Rel Complete and GTP Tunnel Delete
Requests in functions and calls these function in the original place
(rrc_rx_tx()). The same functions are then used in the F1 UE Ctxt Rel
Complete handler to perform the same functionality, i.e. forward the UE
Ctxt Rel Complete message to the MME and free outstanding resources (RRC
context, GTP tunnels, S1 context).

* remove PDCP/RRC contexts
* inform the FlexRAN controller

- add message sender (CU) + handler (CU) and fill with data from ITTI message
- add PLMNID_TO_MCC_MNC and BIT_STRING_TO_TRANSPORT_LAYER_ADDRESS_IPv4 macros
- correct TRANSPORT_LAYER_ADDRESS_TO_BIT_STRING:
  change name to TRANSPORT_LAYER_ADDRESS_IPv4_TO_BIT_STRING, make it send 4B, not 5