chore(provider): use type assertion for port forwarders

internal/provider/provider.go

@@ -5,7 +5,6 @@ import (
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/models"
-	"github.com/qdm12/gluetun/internal/provider/utils"
 )
 
 // Provider contains methods to read and modify the openvpn configuration to connect as a client.
@@ -13,14 +12,6 @@ type Provider interface {
 	GetConnection(selection settings.ServerSelection, ipv6Supported bool) (connection models.Connection, err error)
 	OpenVPNConfig(connection models.Connection, settings settings.OpenVPN, ipv6Supported bool) (lines []string)
 	Name() string
-	PortForwarder
 	FetchServers(ctx context.Context, minServers int) (
 		servers []models.Server, err error)
 }
-
-type PortForwarder interface {
-	Name() string
-	PortForward(ctx context.Context, objects utils.PortForwardObjects) (
-		port uint16, err error)
-	KeepPortForward(ctx context.Context, objects utils.PortForwardObjects) (err error)
-}