Column-major tables

[akshayka]

mo.ui.table expects row-oriented data, which works well in many but not all contexts. In ML and other data applications, data is often stored in columnar formats (parquet, arrow, ...).

We should support columnar data in mo.ui.table. A simple way to get started would be to support pyarrow.Table. Selection on the frontend would be on columns instead of rows.

• [x] Support pyarrow tables
• [ ] Add an option to select by column instead of row