refactor: Meta notifies vec[(target, operation)] to Frontend/Compactor/Compute/Hummock

[Rossil2012]

For now, meta send notification like this:

message SubscribeResponse {
  enum Operation {
    UNSPECIFIED = 0;
    ADD = 1;
    DELETE = 2;
    UPDATE = 3;
    SNAPSHOT = 4;
  }
  common.Status status = 1;
  Operation operation = 2;
  uint64 version = 3;
  oneof info {
    catalog.Database database = 4;
    catalog.Schema schema = 5;
    catalog.Function function = 6;
    user.UserInfo user = 11;
    // for streaming
    FragmentParallelUnitMapping parallel_unit_mapping = 12;
    common.WorkerNode node = 13;
    hummock.HummockSnapshot hummock_snapshot = 14;
    hummock.HummockVersionDeltas hummock_version_deltas = 15;
    MetaSnapshot snapshot = 16;
    backup_service.MetaBackupManifestId meta_backup_manifest_id = 17;
    SystemParams system_params = 19;
    hummock.WriteLimits hummock_write_limits = 20;
    RelationGroup relation_group = 21;
    catalog.Connection connection = 22;
    FragmentParallelUnitMappings serving_parallel_unit_mappings = 23;
    hummock.HummockVersionStats hummock_stats = 24;
  }
}

which indicates that one notification can only invoke one modification on one target. However, many sql statements need to modify a batch of objects in one query. For instance, ALTER DATABASE db OWNER to new_owner needs to modify db's owner and grant CONNECT privilege to new_owner at the same time.
A suggested Proto would be like:

message SubscribeResponse {
  message Info {
    enum Operation {
      UNSPECIFIED = 0;
      ADD = 1;
      DELETE = 2;
      UPDATE = 3;
      SNAPSHOT = 4;
    }
    Operation operation = 1;

    oneof target {
      catalog.Database database = 4;
      catalog.Schema schema = 5;
      catalog.Function function = 6;
      user.UserInfo user = 11;
      // for streaming
      FragmentParallelUnitMapping parallel_unit_mapping = 12;
      common.WorkerNode node = 13;
      hummock.HummockSnapshot hummock_snapshot = 14;
      hummock.HummockVersionDeltas hummock_version_deltas = 15;
      MetaSnapshot snapshot = 16;
      backup_service.MetaBackupManifestId meta_backup_manifest_id = 17;
      SystemParams system_params = 19;
      hummock.WriteLimits hummock_write_limits = 20;
      RelationGroup relation_group = 21;
      catalog.Connection connection = 22;
      FragmentParallelUnitMappings serving_parallel_unit_mappings = 23;
      hummock.HummockVersionStats hummock_stats = 24;
    }
  }
  common.Status status = 1;
  Operation operation = 2;
  uint64 version = 3;
  repeated Info infos = 4;
}

[Rossil2012]

cc @yezizp2012

[github-actions]

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