Figure out correct workflow for adding language switchers

[melissawm]

Summary

Currently, we are targeting pydata sphinx theme and the scientific python hugo theme.

[trallard]

@melissawm you were working on this for the Scientific Python theme no?

[melissawm]

Here is the current situation:

• The Scientific Python Hugo theme already ships a language switcher that can be turned on in the config.yaml file. This is in progress for SciPy.org (see Add language switcher and translations scipy/scipy.org#617 - the switcher is ready, but the translations content is still being set up)
• For pandas.pydata.org, this is a manual process: see ENH: Create infrastructure for translations pandas-dev/pandas#61220
• For the other sites that use different approaches, custom solutions will be needed (I am working on this next).

[trallard]

Wrapping Zarr today (@melissawm)