Updating react-table to v8.
- Migrating the existing table to v8
- Preserving the visuals and logic
What's done?
- Cell components are moved under `Cells` folder
- Old styles for react-table-6 is removed.
- Old types are removed
- All logic was preserved
- Some cell components are removed for simplicity
Fixes: https://github.com/grafana/oss-big-tent-squad/issues/125
