Merge remote-tracking branch 'origin/NR_improvements_for_scheduling_with_DCI_1_0' into integration_2022_wk05

- previously, used magic numbers to designate nFAPI mode
- now, use string values (MONOLITHIC, PNF, VNF, ...)
- Remove printing of the nfapi mode to the console, as it's value is clear from the command-line argument
- Update usages of the --nfapi command-line parameter in scripts and documentation to reflect the change to string values

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

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

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

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

There was a problem testing accelleran cu + oai du + oai ue + rfsim
because accelleran cu configures sdap header for UL but not for DL
and our sdap implementation deals with either "no sdap header at all"
or "sdap headers for both UL and DL".

The code has been modified to deal with the other cases
("sdap header for UL but not DL" and "sdap header for DL but not UL").

has_sdapDLheader and has_sdapULheader have been removed, has_sdap
too, replaced by has_sdap_rx and has_sdap_tx, which makes the code
independant of ue or gnb and is, I think, clearer.

With this work, accelleran cu + oai du + oai ue + rfsim works. We
also have oai gnb + oai ue + rfsim functional for all cases of sdap
header configuration (this won't happen for users, the code of gnb has to
be modified to have sdap header for only ul or only dl). It also works
with a COTS UE for all cases of sdap configuration (again, this won't
happen for users, only "no sdap header" and "sdap headers for both
UL and DL" exist in oai gnb with the current code).

To have other cases, you can edit openair2/RRC/NR/rrc_gNB_radio_bearers.c
and search for NR_SDAP_Config__sdap_HeaderDL_present in there.

To enable sdap, run the gnb with the command line argument
--gNBs.[0].enable_sdap 1

integration_2023_w03

See merge request oai/openairinterface5g!1919

!1880 Fix to schedule NR SRS K2 slots in advance
!1885 cleaning only
!1912 Correctly encode DNN length/APN name
!1913 bugfix: initialize all variables of the 'context' thing
!1914 bugfix: avoid a crash when oai_exit is set
!1915 remove patch in install_simde_from_source()
!1882 CI: Add more RFsim tests, cleanup

- By convention, enums are uppercase in C
- Use it everywhere