Adding new sidelink (SL) variables
Specifically, in this commit, we will begin to implement the #define variables required for synchronization. These variables include offset and payload size values that vary from the Uu interface, in relation to the PSS, SSS and PBCH elements. We also introduce the new sl_mode command line flag, which is used to switch between the Uu interface and SL interface. This will allow us to modify exisitng PSS and SSS functions, without copying complete 5G functions and only changing a few lines to support sidelink mode.