Update WAKU2-METADATA: Move to draft (#6)

Move 66/WAKU2-METADATA to draft.

waku/standards/core/66/metadata.md

@@ -0,0 +1,51 @@
+---
+slug: 66
+title: 66/WAKU2-METADATA
+name: Waku Metadata Protocol
+status: draft
+editor: Alvaro Revuelta <alrevuelta@status.im>
+contributors:
+---
+
+## Abstract
+This specification describes the metadata that can be associated with a [10/WAKU2](../10/waku2.md) node.
+
+## Metadata Protocol
+
+Waku specifies a req/resp protocol that provides information about the node's medatadata. 
+Such metadata is meant to be used by the node to decide if a peer is worth connecting or not. 
+The node that makes the request, includes its metadata so that the receiver is aware of it, 
+without requiring an extra interaction. 
+The parameters are the following:
+* `clusterId`: Unique identifier of the cluster that the node is running in.
+* `shards`: Shard indexes that the node is subscribed to.
+
+***Protocol Identifier***
+
+    /vac/waku/metadata/1.0.0
+
+### Request
+
+```proto
+message WakuMetadataRequest {
+  optional uint32 cluster_id = 1;
+  repeated uint32 shards = 2;
+}
+```
+
+### Response
+
+```proto
+message WakuMetadataResponse {
+  optional uint32 cluster_id = 1;
+  repeated uint32 shards = 2;
+}
+```
+
+## Copyright
+
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).
+
+## References
+
+- [10/WAKU2](../10/waku2.md)