Merge changes Ia9c30515,Ie2fe04cd,I334e82ed,Idf55cc17,Id0815ac6, ...

* changes:
  Properly type bta_ag_at_hsp_cback::tBTA_AG_EVT
  Enum-ify stack/include/btm_api_types::tBTM_IO_CAP
  Enum-ify bta/av/bta_av_int::BTA_AV_RS_
  Enum-ify stack/btm/security_device_record::tBTM_SM4_
  Enum-ify stack/include/l2cdefs::tL2CAP_CONN
  Enum-ify stack/include/btm_api_types::BTM_LE_KEY
  Enum-ify stack/avdt/avdt_int::AVDT_CCB_
  Enum-ify bta/include/bta_ag_api::tBTA_AG_EVT
  Add bta/ag/bta_ag_int::tBTA_AG_API_RESULT::ToString
  Consolidate exits stack/acl/btm_acl::hci_start_role_switch_to_central
  Add BTM_LogHistory to BTM_RemoveSco
  Enum-ify bta/include/bta_ag_api::tBTA_AG_RES
  Add tACL_CONN::SupportsSecureConnections
  Re-log stack/btm/btm_sco::btm_sco_disc_chk_pend_for_modechange
  Re-log bta/av/bta_av_main::bta_av_sco_chg_cback
  Re-log bta/ag/bta_ag_sco::bta_ag_sco_event
  Re-log bta/ag/bta_ag_sco::bta_ag_sco_disc_cback
  Add tACL_CONN::RemoteAddress
  Introduce btm client interface
  Properly include stack/include/hci_error_code::<string>