Maintenance: split each provider in a package

- Fix VyprVPN port
- Fix missing Auth overrides

internal/provider/utils/targetip.go

@@ -0,0 +1,22 @@
+package utils
+
+import (
+	"errors"
+	"fmt"
+	"net"
+
+	"github.com/qdm12/gluetun/internal/models"
+)
+
+var ErrTargetIPNotFound = errors.New("target IP address not found")
+
+func GetTargetIPConnection(connections []models.OpenVPNConnection,
+	targetIP net.IP) (connection models.OpenVPNConnection, err error) {
+	for _, connection := range connections {
+		if targetIP.Equal(connection.IP) {
+			return connection, nil
+		}
+	}
+	return connection, fmt.Errorf("%w: in %d filtered connections",
+		ErrTargetIPNotFound, len(connections))
+}