Add an option for choosing the API path for the UI

[Goodbird-git]

Right now there's an option to move the API endpoints, but I didn't manage to find a way to tell the web UI that the API part is moved.
I see that in the web code the paths are hardcoded to /api/v1, which is a common place for the endpoints of the main service itself.
Thanks in advance for the help and maybe a fix!

[geofmureithi]

This option is available in the pro feature https://apalis.dev/pricing