hfp: send HFP_SUBEVENT_HF_INDICATOR event

hfp_demo: use report_status

hfp_demo: enable Echo Canceling and Noise reduction

hfp: update API docu, remove hfp_hf_activate_echo_canceling_and_noise_reduction

hfp: handle AG send EVR message

hfp: report AG EVR status

hfp: enhanced audio recognition, HF ready for audio

hfp: update examples

hfp_ag: release audio connection only if it was opened before audio VR activated, open audio only if connection does not already exist

hfp_hf: rename voice_recognition_notification functions

hfp: extend HFP_SUBEVENT_VOICE_RECOGNITION_STATUS with status field, rename activated param to state

hfp demoes, use other dongles - to be removed

hfp: report status code

hfp: use acl_handle and sco_handle in events

hfp demos: remove the warning about unhandled HFP meta events

examples: use `btstack_event.h` getters instead of direct array access, use enum to compare status codes

add missing default switch cases

docu: copy editing examples titles

hfp_hf_demo: check status on HFP_SUBEVENT_COMPLETE

hfp_hf_demo: fix build

Use BTSTACK_FILE__ without __ prefix (MISRAC2012-Rule-21.1)

hfp: enhanced call status, fix event and parsing, extend demo

example hfp/hsp: ignore SCO packets if connection handle doesn't match, use HCI_CON_HANDLE_INVALID

hfp_hf_demo: use API calls to access event values, remove ag indicatior status on initial retrieval

hfp: emit ag indicator status