Add MutltibeamRecordingIndexx to cache multibeam frame positions

Author: jp-pino

protobuf_definitions/message_formats.proto

@@ -5,6 +5,7 @@ syntax = "proto3";
 
 package blueye.protocol;
 import "google/protobuf/any.proto";
+import "google/protobuf/duration.proto";
 import "google/protobuf/timestamp.proto";
 option csharp_namespace = "Blueye.Protocol.Protobuf";
 
@@ -1022,6 +1023,15 @@ message MultibeamDiscovery {
   GuestPortDeviceID device_id = 7; // Device ID of the sonar
 }
 
+message MultibeamFrameOffset {
+  google.protobuf.Duration duration = 1; // Duration from the start of the recording
+  uint32 offset = 2; // Offset in bytes from the start of the file
+}
+
+message MutltibeamRecordingIndex {
+  repeated MultibeamFrameOffset frame_offsets = 1; // List of frame offsets
+}
+
 // PersistentStorageSettings defines settings for writing various types of data in the persistent storage on the drone
 //
 // Some of the data is written during factory calibration (acc calibration), while other data is written during user