* fix: repeated fields are packed in proto3
* fix: add new field for shards in metadata protobuffers to avoid breaking change and deprecate original field
This reverts commit dba9820c1f.
We need to revert this commit because
the waku-simulator stopped working. i.e. the nodes couldn't establish
connections among them: 054ba9e33f
Also, the following js-waku test fails due to this commit:
"same cluster, different shard: nodes connect"
* waku_lightpush/protocol.nim: minor changes to make it compile after revert