1. Adding a "SL" frequency for Sidelink mode. The
importance of this variable is to ensure that
when we are in mode 1 (UE+UE+gNB), that the slot
configuration and frequencies do not overlap. This
SL frequency is important for rotation and allows
us to utilize the OFDM modulation and demodulation
functions that already exist in OAI.
2. Adding sl_mode to the command line for proper UE
deployment when in SL mode. sl_mode can be set to 0,
1, or 2. sl_mode 0 indicates no-Sidelink at all,
mode 1 is gNB, UE, and UE (3GPP defines mode numbers).
sl_mode 2 indicated UE to UE communications with no
gNB at all.
3. New functions for calculating the carrier frequency
for SL mode.