⭐ feat: Add protobuf (#171)

This is a second attempt to add protobuf to Nestri, after the first one
failed

---------

Co-authored-by: Philipp Neumann <3daquawolf@gmail.com>
Co-authored-by: DatCaptainHorse <DatCaptainHorse@users.noreply.github.com>

protobufs/messages.proto

@@ -0,0 +1,18 @@
+syntax = "proto3";
+
+option go_package = "relay/internal/proto";
+
+import "types.proto";
+import "latency_tracker.proto";
+
+package proto;
+
+message ProtoMessageBase {
+  string payload_type = 1;
+  ProtoLatencyTracker latency = 2;
+}
+
+message ProtoMessageInput {
+    ProtoMessageBase message_base = 1;
+    ProtoInput data = 2;
+}