Remove FlexRAN

- Remove any FlexRAN code
- Cleanup config files
- Remove LFDS7, libyaml dependencies

docker/scripts/enb_parameters.yaml

@@ -174,12 +174,6 @@
       env: "@ENB_X2_IP_ADDRESS@"
     - key: rrc_inactivity_threshold
       env: "@RRC_INACTIVITY_THRESHOLD@"
-    - key: FLEXRAN_ENABLED
-      env: "@FLEXRAN_ENABLED@"
-    - key: FLEXRAN_INTERFACE_NAME
-      env: "@FLEXRAN_INTERFACE_NAME@"
-    - key: FLEXRAN_IPV4_ADDRESS
-      env: "@FLEXRAN_IPV4_ADDRESS@"
     - key: parallel_config
       env: "@THREAD_PARALLEL_CONFIG@"