BUG/ENH: groupby quantile arraylike fails with integer columns
When columns are integers, `df.groupby(label).quantile(<arraylike>)` fails.
This PR fixes this issue by telling `MultiIndex` to only look for positional levels during an reordering operation.
Two new internal methods in `MultiIndex` class, and one new parameter for `DataFrame.reorder_levels` and `MultiIndex.reorder_levels` are added during the debugging process.

- [ ] closes #30289
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry
