Import statements are in reverse order

[JannikGM]

We have some CSS which is affected by vitejs/vite#3924

We should add the imports in order of appearance.
Imports are correctly iterated in map insertion order.
However, they are added in reverse order due to ast.program.body.unshift.

There might be additional issues when mixing require and import, but we can probably ignore them for now.

[JannikGM]

#54 has massively improved the CSS for us (where order is important), but now we still have a bunch of styling bugs (which went unnoticed during development and testing of #54).
I'll try to debug this further in the near future.

Among them is a bug with "@material-ui/core": "^4.11.4",:

Working Result (how it should look like)

Broken Result (what it currently looks like)

Broken CSS

Broken HTML

[JannikGM]

We solved the problem above with StylesProvider from mui: mui/material-ui#11843 (comment).
We already had a hack using JssProvider from react-jss, but that didn't work in Vite (not sure what it did for webpack).

I'm not sure why there's a difference between webpack and vite for this or why the JssProvider didn't work, but that's not important for us, now that it works.

So I believe everything works as intended now 👍