feat(server/portforward): change route from /v1/openvpn/portforwarded to /v1/portforward

- This route has nothing to do with openvpn specifically
- Remove the `ed` in `portforwarded` to accomodate future routes such as changing the state of port forwarding
- maintaining retrocompatibility with `/v1/openvpn/portforwarded`
- maintaining retrocompatibility with `/openvpn/portforwarded`
- Moved to its own handler `/v1/portforward` instead of `/v1/vpn/portforward` to reduce the complexity of the vpn handler

internal/server/portforward.go

@@ -0,0 +1,52 @@
+package server
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+)
+
+func newPortForwardHandler(ctx context.Context,
+	portForward PortForwardedGetter, warner warner,
+) http.Handler {
+	return &portForwardHandler{
+		ctx:         ctx,
+		portForward: portForward,
+		warner:      warner,
+	}
+}
+
+type portForwardHandler struct {
+	ctx         context.Context //nolint:containedctx
+	portForward PortForwardedGetter
+	warner      warner
+}
+
+func (h *portForwardHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	switch r.Method {
+	case http.MethodGet:
+		h.getPortForwarded(w)
+	default:
+		errMethodNotSupported(w, r.Method)
+	}
+}
+
+func (h *portForwardHandler) getPortForwarded(w http.ResponseWriter) {
+	ports := h.portForward.GetPortsForwarded()
+	encoder := json.NewEncoder(w)
+	var data any
+	switch len(ports) {
+	case 0:
+		data = portWrapper{Port: 0} // TODO v4 change to portsWrapper
+	case 1:
+		data = portWrapper{Port: ports[0]} // TODO v4 change to portsWrapper
+	default:
+		data = portsWrapper{Ports: ports}
+	}
+
+	err := encoder.Encode(data)
+	if err != nil {
+		h.warner.Warn(err.Error())
+		w.WriteHeader(http.StatusInternalServerError)
+	}
+}