BUG: Fixes to msgpack support.
Adds support for IntervalIndex and Interval; fixes Period and
TimedeltaIndex. Closes #19967  and #13463.

- [ ] closes #19967 
- [ ] closes #13463
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry
