Simplify logs in gNB&UE
- reduce the amount of printf() that outputs useless info
- in MAC, PHY, NGAP, RRC, mark some "important" UE events with LOG_A for
better visibility -> can put log_config.global_log_level analysis to
only see important stuff
- in RRC, use some macro to consistently print logs
- track the cellID of a UE in RRC