Favicon does not respect sub path

Hey, very nice project!
I found one small issue, when I set `--uri-prefix="/pastebin"` the favicon does not respect it and always tries to be downloaded from the `https://FQDN/static/favicon.ico` instead of e.g. `https://FQDN/pastebin/static/favicon.ico`.
Quick fix in apache2 will be:
```
# Favicon
Redirect 301 "/static/favicon.ico" "/pastebin/static/favicon.ico"
```