feat: add basic streaming data

Signed-off-by: kjuulh <contact@kjuulh.io>

proto/nodata/v1/nomicon.proto

@@ -8,6 +8,7 @@ service NoDataService {
   rpc PublishEvent(PublishEventRequest) returns (PublishEventResponse) {}
   rpc GetTopics(GetTopicsRequest) returns (GetTopicsResponse) {}
   rpc GetKeys(GetKeysRequest) returns (GetKeysResponse) {}
+  rpc Subscribe(SubscribeRequest) returns (stream SubscribeResponse){}
 }
 
 message PublishEventRequest {
@@ -32,3 +33,14 @@ message GetKeysRequest {
 message GetKeysResponse {
   repeated string keys = 1;
 }
+
+message SubscribeRequest {
+  string topic = 1;
+  string key = 2;
+}
+message SubscribeResponse{
+  string id = 1;
+  google.protobuf.Timestamp published = 2;
+  uint64 offset = 3;
+  bytes value = 4;
+}