nimble/audio: Add initial audio broadcast sink implementation

This adds initial implementation of audio broadcast sink.

nimble/host/audio/include/audio/ble_audio.h

@@ -68,6 +68,9 @@
 /** Broadcast Audio Broadcast Code Size. */
 #define BLE_AUDIO_BROADCAST_CODE_SIZE                             16
 
+/** Basic Audio Announcement Service UUID. */
+#define BLE_BASIC_AUDIO_ANNOUNCEMENT_SVC_UUID                     0x1851
+
 /** Broadcast Audio Announcement Service UUID. */
 #define BLE_BROADCAST_AUDIO_ANNOUNCEMENT_SVC_UUID                 0x1852
 
@@ -539,6 +542,9 @@ struct ble_audio_broadcast_name {
 /** BLE Audio event: BASS - Set Broadcast Code */
 #define BLE_AUDIO_EVENT_BASS_SET_BROADCAST_CODE              5
 
+/** BLE Audio event: Broadcast Sink - Metadata Updated */
+#define BLE_AUDIO_EVENT_BROADCAST_SINK_METADATA              6
+
 /** @} */
 
 /** @brief Broadcast Announcement */
@@ -589,6 +595,21 @@ struct ble_audio_event_bass_set_broadcast_code {
     uint8_t broadcast_code[BLE_AUDIO_BROADCAST_CODE_SIZE];
 };
 
+/** @brief BASS Source Removed */
+struct ble_audio_event_broadcast_sink_metadata {
+    /** Source ID */
+    uint8_t source_id;
+
+    /** BIS Index Mask */
+    uint8_t bis_sync;
+
+    /** Scan Delegator Subgroup: Metadata */
+    const uint8_t *metadata;
+
+    /** Scan Delegator Subgroup: Metadata length */
+    uint8_t metadata_length;
+};
+
 /**
  * Represents a BLE Audio related event. When such an event occurs, the host
  * notifies the application by passing an instance of this structure to an
@@ -647,6 +668,13 @@ struct ble_audio_event {
          * Represents a Broadcast Code baing set in BASS.
          */
         struct ble_audio_event_bass_set_broadcast_code bass_set_broadcast_code;
+
+        /**
+         * @ref BLE_AUDIO_EVENT_BROADCAST_SINK_METADATA
+         *
+         * Represents an update in Broadcast Sink Metadata.
+         */
+        struct ble_audio_event_broadcast_sink_metadata broadcast_sink_metadata;
     };
 };