Implement RPC skeleton for regular/EC volumes scrubbing. (#8187)

* Implement RPC skeleton for regular/EC volumes scrubbing.

See https://github.com/seaweedfs/seaweedfs/issues/8018 for details.

* Minor proto improvements for `ScrubVolume()`, `ScrubEcVolume()`:

  - Add fields for scrubbing details in `ScrubVolumeResponse` and `ScrubEcVolumeResponse`,
    instead of reporting these through RPC errors.
  - Return a list of broken shards when scrubbing EC volumes, via `EcShardInfo'.

weed/server/volume_grpc_erasure_coding.go

@@ -570,6 +570,7 @@ func (vs *VolumeServer) VolumeEcShardsInfo(ctx context.Context, req *volume_serv
 					ShardId:    uint32(si.Id),
 					Size:       int64(si.Size),
 					Collection: v.Collection,
+					VolumeId:   uint32(v.VolumeId),
 				}
 				ecShardInfos = append(ecShardInfos, ecShardInfo)
 			}