Added a note to specify that the memory for the response of a custom endpoint
should be allocated using the heap, as this memory gets freed by the protocomm layer
once it has been passed to the transport layer.
Closes https://github.com/espressif/esp-idf/issues/13263
List of changes in components/wifi_provisioning:
* Manager version is now v1.1
* .proto files and protocomm handler added for sending Wi-Fi scan command and receiving scan results
* Implemented handlers for wifi_scan protocomm endpoint
* Update manager context data structure to hold scan state and results
* scheme_softap now runs Wi-Fi in APSTA mode
* Wi-Fi is started in AP mode when provisioning is started. This is necessary for scan list to work
* Docs updates with information about new wifi_scan endpoint
List of changes in tools/esp_prov:
* Added functions for sending and receiving protobuf messages compatible with wifi_scan protocomm endpoint
* Added feature to display/refresh scan results and accept user selection at runtime
* New functions:
* get_version() : only returns the protocol version string
* has_capability() : check is a capability is present according to proto-ver response
* wifi_scan feature is provided only if the `wifi_scan` capability is present
Other changes:
* Replace recursive mutex with plain mutex
* assert on return value of mutex give / take calls
* replace all calls with macros ACQUIRE_LOCK and RELEASE_LOCK
* some checks added in scanning related private APIs
* free and nullify scanning context and state if service is stopped while ongoing scan
