[Feature Request]: Different ports in "Domain Names" or "Schemes" for Proxy Hosts

Is your feature request related to a problem? Please describe.

Nginx has support for listening on specific ports for specific urls, other than just port 80 and 443. From my understanding of Nginx Proxy Manager, the choice of "Scheme", i.e. "http" or "https", decides what ports it listens to. However, it should be possible to set up for other ports as well.

Here's an example Nginx .conf-file which uses the server_name matrix.example.com in combination with port 8448, something which currently isn't natively supported in Nginx Proxy Manager: https://github.com/spantaleev/matrix-docker-ansible-deploy/blob/master/examples/reverse-proxies/nginx/matrix.conf

Describe the solution you'd like

It should be possible to input a custom port into the "Scheme"-part of the Proxy Hosts.

Describe alternatives you've considered

Filling the port directly in the "Domain Names", e.g. matrix.example.com:8448 and making it possible to remove the Scheme would also be a viable option. Or, for a really desperate solution, allowing the removal of "Scheme" and just requiring all port-listens to be done in the Custom Nginx Configuration would also probably work, but be incredibly bad UX design.

Additional context

Start by tracing how Proxy Hosts expose the Scheme and Domain Names fields and how those values produce Nginx listening configuration. Compare the behavior with the linked matrix.conf example; done means a user can configure a custom port for a host and the resulting Nginx configuration listens on it correctly.