This commit contains work done by Eurecom and by Benetel.

- replaced nr_slot_t with int as it was barely used in the code (also is defined after an lte struct)
- removed use of phy_frame_config_nr from the UE (another file was created in SCHED_NR_UE, still the
  gNB file is used in some tests file at UE side)

- the commit fixes also the selection of the thread_id in TX procedures
- DCI configuration is currently limited to slot 1 and 7

  - The number of nb_dmrs_re at gNB side was set to 6, but here it is assumed
    that there will be no data allocation in OFDM symbols that carry DMRS
  - nb_dmrs_re that is being given as an input to the TBS calculation,
    should be multiplied by the number of DMRS symbols in order to get the total
    number of DMRS REs per RB
  - In the calculation of G, only the number of DMRS per RB in 1 OFDM symbol should
    be given as an input, because inside the function of the G calculation, this
    number is being multiplied by the number of OFDM symbols that carry DMRS

  - The number of nb_dmrs_re at gNB side was set to 6, but here it is assumed
    that there will be no data allocation in OFDM symbols that carry DMRS
  - nb_dmrs_re that is being given as an input to the TBS calculation,
    should be multiplied by the number of DMRS symbols in order to get the total
    number of DMRS REs per RB
  - In the calculation of G, only the number of DMRS per RB in 1 OFDM symbol should
    be given as an input, because inside the function of the G calculation, this
    number is being multiplied by the number of OFDM symbols that carry DMRS

This reverts commit 1462f0e6.

an assertion fails in gnb (need to be fixed)