This reverts commit 1a5874d4.

Integration 2020 wk40 comprises the following udpates:

MR893 ULSCH decode mthread: 
- Enabled parallelization of ULSCH segments decoding, deinterleaving and rx rate matching.
  
MR896 Nsa remove band hardcodings:
- A missing commit from wk39, just a log change   

MR901 NR UE DCI improvements:
- Handling of DCI formats 0_0 and 0_1, including removing hard-coding and scheduling PUSCH with DCI parameters
- Blind decoding of DCIs based on size and format indicator
- Fix for segmentation fault during ULSCH encoding

MR895 support of RA procedure by implementing Msg3 on UE

MR908 NR DL scheduler improvements:
Preliminary work on the DL scheduler
- cleanup of DL scheduler, add interface preprocessor-postprocessor (`NR_UE_sched_ctrl_t`)
- postprocessor can handle multiple UEs. Preprocessor will follow soon (proportional fair scheduler)
- No MAC UE Context creation before end of RA (Msg 3)
These updates do not change anything performance wise (no additional scheduled slots, etc). 
This MR also reduces gNB log.

-Since the aim of itti RRC_SUBFRAME_PROCESS message (MAC->RRC) is to trigger an itti X2AP_SUBFRAME_PROCESS message (RRC->X2AP), avoid creating
RRC_SUBFRAME_PROCESS message if x2ap task is not enabled. Not sure if this is the best solution. We could also avoid only sending the second itti X2AP_SUBFRAME_PROCESS message.

The name NR_UE_list_t is misleading: beyond being a simple "list", this
structure carries all/most UE-related MAC information. If at all, it is
a container for multiple lists. The next commit introduces a
NR_UE_list_t structure that organizes UEs in lists such that it is
easier to go through the UEs.

Conflicts:
	openair1/PHY/NR_UE_TRANSPORT/nr_ulsch_ue.c
	openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c
	openair2/NR_UE_PHY_INTERFACE/NR_IF_Module.c