Subpath installation again (on Apache httpd)

[cbertelli]

I ask to reopen this issue Subpath installation #174 as I'm trying to find a viable configuration for Apache to serve https://example.com/listmonk.
I added a comment under the original issue, but being unable to reopen it, I made a new one pointing to the old one. Sorry.

[knadh]

I'd done a bunch of experiments around this. I don't know if this is possible at all, given how the JS frontend build works, where it hardcodes the path during build time for internally loading JS assets with no way to make it dynamic.