example/a2dp_sink_demo: assign command status

a2dp_sink_demo: add HAVE_BTSTACK_AUDIO_EFFECTIVE_SAMPLERATE

a2dp_sink_demo: use built-in btstack_sample_rate_compensation module

a2dp_sink_demo: fix start/stop, discard pending data on stream stop

a2dp_sink_demo: adding sample rate compensation

example/le_streamer_client: use gatt_client_request_to_write_without_response

example: gatt_streamer_server and le_streamer_client report DLE and PHY changes

a2dp:emit A2DP_SUBEVENT_STREAM_ESTABLISHED with if connection fails

example/pan_lwip_http_server: only init lwip if HAVE_LWIP is not defined

example: fix warnings

a2dp_sink_demo: report failed outgoing connection

examples: unify status stdout format

example/a2dp_source_demo: fix build

Merge branch 'develop'

# Conflicts:
# CHANGELOG.md

example/a2dp_source_demo: add command to scan and connect to Bluetooth speaker by class of device

example/a2dp_source_demo: keep selected audio source

example/spp_counter: remove outdated comments

example: fix makefile build

example/a2dp_sink: pass media config by pointer

example/a2dp_sink: fix tracking of avrcp playback status

example/a2dp_sink: separate stream_endpoint, a2cp_connection and avrcp_connection, track stream and play states

example/a2dp_sink: store remote bd_addr

example/a2dp_sink: collect per connection data in single struct

hfp_hf_demo: answer pin code request

avrcp_browsing_client: add compile error if ERTM is not enabled