feat: Add metrics for Parquet DataSource

[Meghajit]

For a dagger running with Parquet Source, some additional metrics might be needed in order to gauge the performance of the source, file reader behaviour, checkpointing behaviour as well as the split assigner behaviour( files added, files skipped). Also, for the existing metrics, if any changes are required so as to be consistent across the multiple sources, then that needs to be taken care of as well.