- sorted out according to recurring logic that wants function
  prototypes in separate files from data struct and constants
  definitions, variables in separate .c files with inclusion
  of "extern" header files
- moved function prototypes to resective header files
- moved data structures and constants to respective header files
- merged unnecessary mac.h file into mac_defs.h @ MAC UE
- moved const variables suchs as tables to respective .c files
- moved extern references to respective extern.h files

- enhancement of DL indication flow for Msg2 (RAR)
- merging interface procedures to handle DLSCH and RAR together
- better separation of MAC and PHY functionalities
- cleanup of double ambiguous functions to process RAR
- merging functions to process TA command into the ue_ta_procedures function
- enhancement of logging and formatting in the process

- moved fill_dl_indication to phy procedures
- introduced a new function to fill the RX indication
- replaced redundant configuration code with the fill functions
- extended the function to fill the rx indication
- handling different dl pdus types
- cleanup of redundant code

- removed unused arguments to phy functions
- removed irrelevant conditions on UE run mode
- replaced hardcoded param with PHY UE stored value

- new function called ue_ta_procedures
- this makes the code more easier to read
- small cleanup was also done

This commit contains work done by Eurecom and by Benetel.

- added some descriptions to the code
- fixed hardcoded factors
- removed commented out and unused code
- phy_procedures_nrUE_RX: removed unused do_pdcch_flag
- updated LTE naming to 5G

- Updated PRACH procedures and general code formatting
- gNB msg1 handling and RAR generation
- general bug fixing
- formatting
- missing headers
- RAR handling.

Signed-off-by: Raphael Defosseux <raphael.defosseux@eurecom.fr>

Maintenance of Uplink Time Alignment. Introduced control on TA transmission and TA update application.

- ta_timer at gNB side to control the transmission of TA to the UE. This is now happening every 20 slots.
- when the timer resets gNB is now transmitting the TA whether it is zero or not.
- introduced struct NR_UL_TIME_ALIGNMENT_t to handle configuration of time alignment related parameters.
- UE PHY RX: is now triggered through a flag when to store the TA command, the frame and slot
  when the application should occur.
- UE PHY TX: when the tx frame and slot match the time alignment configuration, it process the TA command and applies the
  TA update

- Initial gNB DLSCH and UE spec scheduling implentation
- MAC PDU generation (including header as per TS 38.321)
- MAC PDU processing at UE side with extracion of TA updates
- General code cleanup
- Introduced NR MAC COMMON folder, moved common files here

remove RRC_VERSION macros, simplify build-oai and CMakefile.txt accordingly, get rid of remaining compilation warnings (opt module improperly merged and patch asn1c files with tests against max 64 bits integer value)

 - dci_request and dl_indication for PBCH now also on stack
 - fixed type of nrUE_config (was using structure for gNB before)
 - added configuration of PBCH to phy_config_request and using this config now in phy_procedures_nr_ue
 - we need to add configuration of PDCCH and PDSCH also to phy_config_request (there are still some hardcoded parameters)
 - removed UL scheduling for now

- adding SCHED_NR_UE_LIB to ulsim compilation library
- fixing linking compilation problems
- using fapi_nr_dci_pdu_rel15_t struct to initialize PUSCH
- test_input random data is set in phy_procedures_nrUE_TX instead of ulsim