- moved remaining PUSCH PDU configuration from ULSCH
  procedures entirely to MAC
- introduced a function for DMRS RE configuration
- cleaned up redundant code in ULSCH procedures
- fixed TBS computation for Msg3

- fetching resource allocation from higher layer
- sorting out config for the remaining parameters

- redundant code for the configuration of the scheduled_response was removed
- scheduled response is not needed to be stored in the NR_UE_MAC_INST struct as it passed to the function right away

- tx_request is filled in the nr_scheduled_response upon the presence tx data

- calling nr_ue_scheduled_response after pdu preparation
- increasing the number_pdus before response scheduling
- resetting after dl/ul config pdu handling

- removed superfluos code
- formatting
- fixed logging
- removed redundant nr_get_dci_size (replaced by nr_dci_size)
- removed unused and long-time commented out functions @ UE side

- extraction of resource allocation from Msg2
- configuration of Msg3 PDU
- Msg3 scheduling
- MAC/PHY interface adaptations

also do some code cleanup while at it...

- Check for timing_advance update _after_ RX (and TX) processing
- Update writeBlockSize when timing_advance value changes (for USRP)
- ignore timestamp when pre-reading the first OFDM symbol of a frame (for rfsimulator)
- do not busy wait for a finished RX-TX thread, use blocking wait instead

remove "pdsch_vars_flp", "pdsch_vars_SI", "pdsch_vars_ra", "pdsch_vars_p" and "pdsch_vars_MCH", use per thread "pdsch_vars" instead

# Conflicts:
#   openair1/PHY/NR_UE_TRANSPORT/nr_ulsch_ue.c

Develop integration: 2020 week 33

The following Merge Requests are included:

* MR [849] : Implement Message2 (RAR) reception for NR-UE
* MR [870] : Fix softmodem restart
* MR [871] : Fix support for MIMO in rf-simulator
* MR [873] : BUILD: fix for new API on load_softscope

- Ensure that tx slot processing is done by the time trx_write_func() gets called

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

Conflicts:
	targets/ARCH/rfsimulator/simulator.c

See merge request oai/openairinterface5g!869

Develop Integration Branch : 2020 week 31

The following Merge Requests have been included:

* MR [861] : Fixes for buffer overrun when L1 information is cleared upon UE removal in
* MR [863] : Small fixes
* MR [864] : Fixed the bug no supporting CellId more than 256
* MR [865] : Fix to have the sony 5g connect in NSA mode
* MR [867] : CI improvements for OCP-enb testing and NSA FR1 testing
* MR [868] : Add chansimuparams

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

Set n_dmrs_cdm_groups = 1 for now.
Should be fixed accordingly to TS 38.214 section 5.1.6.2
using tables 7.3.1.2.2-1, 7.3.1.2.2-2, 7.3.1.2.2-3, 7.3.1.2.2-4 of TS 38.212