[StreamChatPersistence] Add initial implementation

Signed-off-by: Sahil Kumar <[email protected]>

packages/stream_chat_persistence/lib/src/entity/channel_queries.dart

@@ -0,0 +1,14 @@
+import 'package:moor/moor.dart';
+
+@DataClassName('ChannelQueryEntity')
+class ChannelQueries extends Table {
+  TextColumn get queryHash => text()();
+
+  TextColumn get channelCid => text()();
+
+  @override
+  Set<Column> get primaryKey => {
+        queryHash,
+        channelCid,
+      };
+}