Feature Request: ability to have multiple proxy sections in a single service

Currently Kamal assumes the application only has single exposed HTTP/HTTPS port, and supports routing multiple hosts or path prefixes to that port. But real deployment requirements can be very different:

• some services expose and proxy multiple ports serving HTTP in a single application
• some services may consist of multiple applications deployed in a single container

For example, an application may have back office area or an admin panel, that must be exposed via proxy, but should only be accessible on a different port. which would allow to secure access using a firewall, VPN, etc. You can't use a separate service for this, as it's always deployed together. Such configuration currently is not possible without scripting and is likely prone to errors if you implement it yourself via hooks.

Instead, Kamal could accept multiple "proxy sections", where each section can have own app port, published ports, routing (host and/or prefix based), SSL etc. Kamal proxy supports multiple applications on a single proxy, but it seems to be intended for fully separate services.