Investigate moving community description to a separate shard

[plopezlpz]

Community description messages include the member list and it is relayed often, it is increasing bandwidth in shard 32 (for communities without a shard specified), it could be advantageous to post it into a separate shard (e.g.: 128) via light-push and get them using store query.

The goal is to reduce bandwidth in the shard used for content messages where status desktop nodes would be participating in relay.

Also track the bandwidth saved, there is a PR that will record the bandwidth by message type here:
https://github.com/status-im/telemetry/pull/74/files
Once merged we could ideally see the gains of moving self-addressed messages to a different shard