Add an example section about how to use Parquet/ORC library options

Our current doc does not explain we are passing the data source specific options to the underlying data source:

• https://spark.apache.org/docs/latest/sql-programming-guide.html#manually-specifying-options

We can add some introduction section for both Parquet/ORC examples there. We had better give both read/write side configuration examples, too. One example candidate is `dictionary encoding`: `parquet.enable.dictionary` and `orc.dictionary.key.threshold` et al.