ignoring command line paramters clock_source and time_source in lte-softmodem and harmonizing it with nr-softmodem
time_source and clock_source handled separately in usrp_lib.cpp

ENABLE_ITTI macro removal, modified telnet server to support all executables, modified record player to finalize switch to run-time option and allow usage with any device

fix phy simulators build Pb: move snr_dB global to simulation code, add a channel mode section in configuration for snr_dB ,add a parameter flag in the config module to allow omitting prefix when modifying a parameter (for compatibility of -s option)

* Instead of partly initializing in read_config_and_init(), everything of
  PDCP is initialized in main() of lte-softmodem
* Omit RC.rrc access in RRU through checking of RC.nb_inst > 0
* Includes FlexRAN, i.e. do not start FlexRAN in RRU
* Function pointers to PDCP functions have to be set explicitly (avoid
  confusion of multiply setting function pointers)