Image asset urls

This plugin may be helpful: https://www.npmjs.com/package/postcss-url/v/7.3.2

Some experimental config:
https://git.drupalcode.org/project/unocss_starter/-/blob/0.2.x/demo/unoc...

Seems like settings the base path in vite.config.js to './' is working. Needs some testing.

Fix default image paths.

SVG and images get inlined in the css. Large image files get copied to dist.