Add some features to make local table work more interesting for KnoxShell.
- Export to CSV and JSON.
- Load from JSON and CSV from local disk or from URL.
- Join KnoxShellTables by matching on a common key.
- Filter a KnoxShellTable with RegEx on a given column.
- Add KnoxShellTableCell support to be able to retrieve a cell and apply changes to both values of the cell as well as header for the col to a given table.