Is your feature request related to a problem?

There are still missing methods on DataTree and I did not find an issue tracking those.

• Did I miss that?
• Is there a reason they are missing?

e.g.:

• broadcast_like
• dropna
• transpose
• ...

(I am sure there are more but these are the ones I need.)

Describe the solution you'd like

No response

Describe alternatives you've considered

We could use map_over_datasets(xr.Dataset.transpose, dt) but (1) that's annoying, (2) obj.transpose() would work for DataTree and Dataset etc.

Additional context

No response