Support relative asset loading for router-less apps

## Feature Request

Currently, if I build a dioxus web app bundle, it will load assets using absolute paths. So, one has to consider the path the app will be hosted under at build time.

Dioxus could use relative paths to load those assets instead.

This wouldn't really work for multi-page apps that use a router, since relative path will depend on the navigated location, but for single-page apps this should work, and would simplify deployment greatly.

## Implement Suggestion

I don't know