Use `map_overlap` for rolling reductions with Dask

[phofl]

• [ ] Closes #xxxx
• [ ] Tests added
• [ ] User visible changes (including notable bug fixes) are documented in whats-new.rst
• [ ] New functions/methods are listed in api.rst

This enables Dasks map_overlap for rolling reductions, the previous issues with memory consumption are now handled in map_overlap as far as I can tell

[phofl]

Looks like CI is green, anything I should check here?

cc @dcherian FYI

[dcherian]

I guess this means I can simplify #9720 since we don't need it for the built-in reductions?

[phofl]

I guess this means I can simplify https://github.com/pydata/xarray/pull/9720 since we don't need it for the built-in reductions?

unfortunately no, more than one windowing dim takes the construct path :(

[phofl]

The doc build thing is unrelated

[max-sixty]

Looks good!

[phofl]

Failures seem unrelated