EXPM: re-evaluate experimental
leave as experimental or change docs
- [ ] eval/query
- [ ] CustomBusinessDay
- [x] msgpack #27084 (deprecating)
- [ ] BigQuery
- [x] Panel4D -> deprecated
- [x] PanelND -> deprecated
- [ ] SQL changes
- [ ] r*flex methods
- [ ] get_options_data (#5602)
- [ ] DataFrame.style
