Merge changes I9f76c7f7,Id5863a3c,I070cc0c0,I09f31af5,I4d4f2b79, ...

* changes:
  btm_log: Add pairing state changes
  Move stack/include/bt_types::FLOW_SPEC => stack/l2c
  Move stack/include/::btm_api into btm_ble_api
  Include security_client_callbacks
  Break out security callbacks stack/include/security_client_callbacks
  Introduce stack/include/sco_client_callbacks
  Add stack/acl/btm_acl::SupportTransparentSynchronousData
  Expand stack/include/btm_client_interface
  Add explict FALLTHROUGH_INTENDED to package
  Re-log stack/rfcomm/rfc_mx_fsm::rfc_mx_sm_execute
  Re-log stack/btm/btm_sec::BTM_SetSecurityLevel
  Re-log stack/btm/btm_sec::btm_sec_mx_access_request
  Re-log stack/btm/btm_sco::BTM_SetEScoMode
  Re-log stack/btm/btm_sco::btm_send_connect_request
  Re-log stack/btm/btm_ble_gap::BTM_BleGetVendorCapabilities
  Re-log stack/btm/btm_ble::btm_ble_set_random_address
  Re-log stack/acl/btm_pm::
  Re-log bta/av/bta_av_api::BTA_AvStart
  Re-log bta/ag/bta_ag_main::bta_ag_api_result
  Add stack/include/btm_api_types::security_mode_text
  Add stack/btm/security_device_record::security_state_text
  Streamline stack/btm/btm_sco::btm_sco_connected
  Enum-ify bta/include/bta_api::tBTA_DM_PM_ACTION_BITMASK
  Canonicalize stack/gatt/bta_gattc_act::bta_gattc_cl_cback
  Use proper types btm_sco_connected tHCI_STATUS
  Use tBTA_AG_SCB::ToString
  Re-log stack/btm/btm_sec::btm_sec_disconnected
  Streamline stack/btm/btm_sec::btm_sec_disconnect
  Stat-ify stack/gatt/att_protocol

diff --cc stack/acl/btm_acl.cc
Simple merge

diff --cc stack/btm/btm_sco.cc
Simple merge

diff --cc stack/include/acl_api.h
Simple merge