Add RSSI threshold-based power control for PUSCH and PUCCH

- Introduced new configuration parameters `pusch_RSSI_Threshold` and `pucch_RSSI_Threshold`
  (MACRLC section)
- Added `nr_limit_tpc` function in `gNB_scheduler_primitives.c` to limit TPC based on RSSI
  threshold.
- Integrated `nr_limit_tpc` in PUCCH and PUSCH power control

Example Configuration

puxch_RSSI_Threshold takes value between -1280 and 0 and is mapped to range -128.0 dBm/dBFS
to 0.0 dBm/dBFS in 0.1 dB increments. Unit depends on RSSI reporting config.

pucch_RSSI_Threshold = -500;  # Set the PUSCH RSSI threshold to -50.0dBm/-50dBFS
pucch_RSSI_Threshold = -600;  # Set the PUCCH RSSI threshold to -60.0dBm/-60dBFS

doc/MAC/mac-usage.md

@@ -197,6 +197,11 @@ In the `MACRLCs` section of the gNB/DU configuration file:
   beams, depending on hardware switching performance
 * `beams_per_period`: set of beams that can be simultaneously allocated in a
   period (`beam_duration`)
+* `pusch_RSSI_Threshold`: Value between -1280 and 0 which maps to range
+   from -128.0 dBm/dBFS to 0.0 dBm/dBFS. This limits PUSCH TPC commands in
+   case RSSI reaches the threshold and prevents ADC railing. Unit depends on
+   RSSI reporting config.
+* `pucch_RSSI_Threshold`: Same as above but for PUCCH
 
 In the `gNBs` section of the gNB/DU configuration file: some of the parameters
 affect RRC configuration (CellGroupConfig) of a UE, and are therefore listed