Add `integrate` and some `cumulative_integrate`

[erogluorhan]

I would add integrate and some cumulative_integrate. The latter is not yet available on xarray, but would be awesome to implement. A nice example to have on the docs that combine derivatives and integrations could be getting some model output to compute geostrophic velocities applying thermal wind to the buoyancy field.

Originally posted by @iuryt in https://github.com/UXARRAY/uxarray/discussions/46#discussioncomment-2747066