Add gRPC interface function to request user fields supported by a board/protocol combination

Author: silvanocerza

Diff for: commands/daemon/daemon.go

@@ -349,6 +349,12 @@ func (s *ArduinoCoreServerImpl) UploadUsingProgrammer(req *rpc.UploadUsingProgra
 	return stream.Send(resp)
 }
 
+// SupportedUserFields FIXMEDOC
+func (s *ArduinoCoreServerImpl) SupportedUserFields(ctx context.Context, req *rpc.SupportedUserFieldsRequest) (*rpc.SupportedUserFieldsResponse, error) {
+	res, err := upload.SupportedUserFields(ctx, req)
+	return res, convertErrorToRPCStatus(err)
+}
+
 // BurnBootloader FIXMEDOC
 func (s *ArduinoCoreServerImpl) BurnBootloader(req *rpc.BurnBootloaderRequest, stream rpc.ArduinoCoreService_BurnBootloaderServer) error {
 	resp, err := upload.BurnBootloader(

Diff for: rpc/cc/arduino/cli/commands/v1/board.pb.go

@@ -120,6 +120,11 @@ service ArduinoCoreService {
   rpc UploadUsingProgrammer(UploadUsingProgrammerRequest)
       returns (stream UploadUsingProgrammerResponse);
 
+  // Returns the list of users fields necessary to upload to that board
+  // using the specified protocol.
+  rpc SupportedUserFields(SupportedUserFieldsRequest)
+      returns (SupportedUserFieldsResponse);
+
   // List programmers available for a board.
   rpc ListProgrammersAvailableForUpload(
       ListProgrammersAvailableForUploadRequest)