Add documentation regarding reading Parquet files #1376
Description
- add page regarding reading from Parquet files in our Data Sources https://kotlin.github.io/dataframe/data-sources.html, you could insert an image and short description of the format
- it should contain actual information about Parquet file format and typical use-cases, where it could be created
- https://parquet.apache.org/ -refer on it
- notice that we support only reading via Apache Arrow
- add information that we have an example with rich Readme.md which demonstrates data engineering use-case for the https://github.com/Kotlin/dataframe/tree/master/examples/idea-examples/spark-parquet-dataframe
- update all documentation parts where we are mention reading from the different file formats like CSV
- Mention we don't support structered data! Add inner / Struct type support in Arrow #536
- Add a note in the android documentation that we cannot read parquet files, as Arrow is not supported there