- Setting the payload to random data instead of all zeros at the Tx side

- Handling "nb_symb_sch" equal to 0 in "phy_procedures_nrUE_RX" which prevents
  entering "nr_ue_pdsch_procedures"

- Handling symbol loop problem in "nr_ue_pdsch_procedures"

- Handling resource block loop problem in "nr_rx_pdsch"

phy_simulators do compile, but dlsim&nr_(ulsch/dlsch/pbch)sims do not pass tests + Raphael's CI patch applied.

--phy_simulators warning removals, except for nr_dlsim. Polar coding old implementation's approximation and a priori information options needs to be corrected or removed

- UE channel estimation no longer done in slot_fep. Also created dedicated memory for channel estimates of different channels
- using nr_extract_dci_info instead of nr_generate_ue_ul_dlsch_params_from_dci as in phy_procedures_nr_ue. The latter was only a (poor) wrapper and not doing what the name suggests. also with FAPI things have to be done differently now. This will come in a next commit.
- other minor changes to remove warning
prepreatory changes