[Feature] Base URL config option

[BitterSweetcandyshop]

Is your feature request related to a problem? Please describe. just setting up nginx configs and I noticed I was struggling because everytime I would load from "https://mydomain.com/romm" romm would look for "https://mydomain.com/assets" when it's really under "https://mydomain.com/romm/assets"

Describe the solution you'd like under enviroment in the docker config to add a BASE_URL=romm

Describe alternatives you've considered Lots of struggling with nginx to make it work, all the programs I currently use support this one way or another

Additional context I'm not great with nginx really, but it would be nice to also see some proxy examples for people to use.

[gantoine]

It would be nice to also see some proxy examples for people to use.

Personally I use subdomains like games.domain.com, as I found support for subpaths tends to be limited when self-hosting. If there's a clean way to implement this on a code-level (which doesn't require manually updating every history.push and /assets src) I'm all for it.