ENH: mul(Tick, float); simplify to_offset
- [ ] closes #xxxx
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

This will let us remove Resolution.get_stride_from_decimal
kk if u can rebase rebased+green