UE directory splits, creation of UE-specific files, common UE/eNB files and extraction of UE/common components from eNodeB files. renaming of files to minimize common names across directories (i.e. defs.h, vars.h, extern.h)

Merge branch 'develop-uedirectorysplit' of https://gitlab.eurecom.fr/oai/openairinterface5g into develop-uedirectorysplit

Conflicts:
	cmake_targets/CMakeLists.txt
	openair1/PHY/LTE_ESTIMATION/lte_adjust_sync.c
	openair1/PHY/LTE_UE_TRANSPORT/dci_ue.c

Summary of changes:
- free configmodule memory when shutting down
  It is possible to restart the lte-softmodem via the FlexRAN controller.
  For this to work, the end_configmodule() method needs to be called when
  shutting the lte-softmodem down so that the configuration can be read
  again during a restart.
- Feature agent
  Implements an agent ID, consisting of the OAI module ID, the OAI eNB ID
  and the cell ID. The agent reads this information in its configuration
  read function and forwards it to the controller.
  This MR also contains some code forwarding SI info to the controller.
- various bugs fixed
  - remove start_background_system from eNB softmodem
  - fix memory leak when doing traffic
  - disable ITTI dump (does someone uses this?)
  - disable U-plane inactivity timer: it's very simple to put this back,
    but as of now it comes with its own problems that we don't have time
    to check/fix

Only ulsim and dlsim compile. The others (dlsim_tm4 pucchsim prachsim
pdcchsim pbchsim mbmssim) have been disabled.

Command line to compile: ./build_oai --phy_simulators

This is only needed by the UE code, to setup IP settings.
The eNB does not need this. (To be reverted if this is
wrong.)

When doing TCP downlink traffic with iperf for several
hours, the memory consumption of lte-softmodem does not
stop to grow.

After analysis, this commit seems to be the only fix needed.
To be checked somehow.

If anyone needs it, it's a simple matter of reverting this
basic commit.

It is annoying and does not seem to work properly.
To be checked/reworked if needed.

Keep in mind that we also want oaisim to be functional.

if the FlexRAN agent is disabled, do not read all the data and skip reading
of more information

The agent_id is a uint64 consisting of: module ID (i.e. mod_id, the several
instances of OAI at once, 16 bit), the enb_id from the configuration file (32
bit) and the cell_id from the configuration file (16 bit).

The module ID is part of the agent ID but it is easier to have it directly in
the struct.

It is possible to restart the lte-softmodem via the FlexRAN controller. For
this to work, the end_configmodule() method needs to be called when shutting
the lte-softmodem down so that the configuration can be read again during a
restart.

The PHICH was not programmed for the last round (4) because it was
not programmed in rx_sdu but in schedule_ulsch_rnti, only in case
of a programmed retransmission (there is obviously no retransmission
programmed after the last round).

The case of Msg3 is not handled. To be done somehow.

The code is too complex. This commit may not be enough.

Summary of changes:
- bug fix in the FlexRAN API (correct a check)
- bug fix for sending the right RNTI in a FlexRAN message
- fixes small bug in ulsim which kills one RX antenna in channel simulation.
  Another simple but bad bug in ulsch_demodulation.c (bad access of avgU
  array). This probably resulted in a performance degradation for non-ideal
  channels, even for 1 antenna. The avgU was read in position 1 instead of
  0 for 1-antenna and in positions 1 and 2 instead of 0 and 1 for 2-antennas.
- work from Nokia:
    1) shared library loader, with integration for oai devices, encoder and telnet server
    2) telnet server (use build-oai --build-telnetsrv option and --telnetsrv softmodem option)
    3) UE/eNB in different executables (lte-uesoftmodem and lte-softmodem + noS1 variants)
    4) config module fixes and extensions
    5) very preliminary NB-IoT integration preparation, using shared lib loader ( use make NB-IoT to build, after building the eNB softmodem)
    6) Rename NB-IoT configuration sources from nbiot_ to NB-IoT_ to be consistent with other NB-IoT developments.
- various bugs fixed:
  - try to avoid "buffer full" problem when pushing DL traffic
  - add a stop_rf function in the RU
  - cleanup - remove unnecessary calls to get_cpu_freq_GHz
    (was disrupting realtime at startup, generating lots of UU and LL)
  - cleanup MAC PDU generation

Compilation with Rel10 is not functional anymore.
Compilation of unitary simulator is not functional anymore.

End of line character has to be unix-style, not dos-style.

* bug fix in the FlexRAN API (correct a check)
* bug fix for sending the right RNTI in a FlexRAN message

fixes small bug in ulsim which kills one RX antenna in channel simulation.
Another simple but bad bug in ulsch_demodulation.c (bad access of avgU
array). This probably resulted in a performance degradation for non-ideal
channels, even for 1 antenna. The avgU was read in position 1 instead of
0 for 1-antenna and in positions 1 and 2 instead of 0 and 1 for 2-antennas.