feat: add operations endpoint to get topics

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

proto/nomicon.proto

@@ -6,6 +6,8 @@ package nodata;
 
 service NoData {
   rpc PublishEvent(PublishEventRequest) returns (PublishEventResponse) {}
+  rpc GetTopics(GetTopicsRequest) returns (GetTopicsResponse) {}
+  rpc GetKeys(GetKeysRequest) returns (GetKeysResponse) {}
 }
 
 message PublishEventRequest {
@@ -19,3 +21,14 @@ message PublishEventRequest {
 message PublishEventResponse {
   
 }
+
+message GetTopicsRequest {}
+message GetTopicsResponse {
+  repeated string topics = 1;
+}
+message GetKeysRequest {
+  string topic = 1;
+}
+message GetKeysResponse {
+  repeated string keys = 1;
+}