docs: document port

Changed files
+1
docs
src
internal
+1
docs/src/internal/ports.md
···
<!-- note: grafana uses unix sockets instead. -->
- `3xxxx`: Service ports
- `35xxx`: exposed docker container ports
···
<!-- note: grafana uses unix sockets instead. -->
- `3xxxx`: Service ports
+
- `34723`: miniflux
- `35xxx`: exposed docker container ports