use eventgroup to sync spp_vfs_write
each connection has a switch_delay_timer not sharing a one
revert functions like spp_find_slot_by_xxx
fix vfs read bug when peer close
1. Add logs for SPP not enabled successfully
2. Add information to Applicatioin layer that the A2DP is connecting to peer device
Regular BTC and BTU Task name & Add BTC Init protection
1. Regular the BTC Task Name to Close a Github issue
Closes https://github.com/espressif/esp-idf/issues/4966
2. Add BTC Init failure protection
3. Regular BTU Task Name with BTC
4. Correct the comment of
a. SDP_ServiceSearchRequest and SDP_ServiceSearchRequest2
b. l2cu_create_conn_after_switch
5. Correct comment of esp_bt_hf_vra();
6. Fix cpp compilier region
