Fix Coverity Scan CID 300425 (Using uninitialized value req_msg when calling flexran_agent_stats_request.)

Fix Coverity Scan CID 300427 (Variable ue_report going out of scope leaks the storage it points to.)

Fix Coverity Scan CID 300461 (Variable stats_reply_msg going out of scope leaks the storage it points to.)

Fix Coverity Scan CID 300504 (Using uninitialized value timer_msg when calling flexran_agent_stats_request.)

For whatever reason most of the files had their permission
changed from 644 to 755, which is not wanted.

* RRC and MAC might sort users differently
* therefore, we have to "reverse lookup" the MAC ID from the RNTI when filling
  user info
* For this purpose, add RAN API function flexran_get_mac_ue_id_rnti()

* the RAN API RRC part now takes rnti and does not look it up in the MAC every
  time again
* the function flexran_get_aperiodic_cqi_rep_mode() has been changed to return
  a proper protobuf variable, not OAI typedef

Use common log mechanism in layer 3, mapping specific macros to common ones and extending common log utilities to support specific layer3 requirements

remove compilation warnings, especially when disabling T_TRACER. enhance LOG_M macro implementation, introduce LOG_DEBUG_XXX macro to replace #ifdef DEBUG_XXX