Maintenance: split each provider in a package

- Fix VyprVPN port
- Fix missing Auth overrides

internal/provider/nordvpn/connection.go

@@ -0,0 +1,39 @@
+package nordvpn
+
+import (
+	"github.com/qdm12/gluetun/internal/configuration"
+	"github.com/qdm12/gluetun/internal/constants"
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/provider/utils"
+)
+
+func (n *Nordvpn) GetOpenVPNConnection(selection configuration.ServerSelection) (
+	connection models.OpenVPNConnection, err error) {
+	var port uint16 = 1194
+	protocol := constants.UDP
+	if selection.TCP {
+		port = 443
+		protocol = constants.TCP
+	}
+
+	servers, err := n.filterServers(selection)
+	if err != nil {
+		return connection, err
+	}
+
+	connections := make([]models.OpenVPNConnection, len(servers))
+	for i := range servers {
+		connection := models.OpenVPNConnection{
+			IP:       servers[i].IP,
+			Port:     port,
+			Protocol: protocol,
+		}
+		connections[i] = connection
+	}
+
+	if selection.TargetIP != nil {
+		return utils.GetTargetIPConnection(connections, selection.TargetIP)
+	}
+
+	return utils.PickRandomConnection(connections, n.randSource), nil
+}