[WIP] Plain bootswatch theme (with picker)

[SvenDowideit]

TODO:

• need to make the split resize lines visible
• test to see if this works from a release offline :)
• defer - this uses bootswatch 4.4.1, and needs work to use 5.1 / to keep up with bootstrap and bootswatch

[nathanleclaire]

Cool. I think we need to figure out where the balance between Tailwind and Bootstrap is, cause now we have both in play. This is doubling down on Bootstrap. Whereas the easiest path forward for, e.g., grids in other parts of the app given what we have now is Tailwind. And some UI components are tightly coupled to Tailwind as-is as well. I'm not sure the answer... let's chew on it for a bit.

This direction definitely feels a bit like a future "breaks my workflow / styling theme" risk.