MAC: use seq_arr to group LC configuration

Use a common structure nr_lc_config_t to group LC configuration for one
logical channel. Use seq_arr for simple lookup, adding, removing of
elements without manual indexing logic.

This commit retains the previous logic of adding/releasing LCs through
the process_CellGroupConfig(), although we know while building the
CellGroupConfig if we add/release LCs. The next commit fixes this.

CMakeLists.txt

@@ -1458,6 +1458,7 @@ add_library(L2_NR
   ${MAC_NR_SRC}
   ${GNB_APP_SRC}
   )
+target_link_libraries(L2_NR PRIVATE ds alg)
 
 add_library(e1_if
   ${NR_RRC_DIR}/cucp_cuup_direct.c