Mobile (#735)

Initial modification to support mobile client

Export necessary interfaces for Android framework

client/internal/dns/server_android.go

@@ -0,0 +1,32 @@
+package dns
+
+import (
+	"context"
+
+	nbdns "github.com/netbirdio/netbird/dns"
+	"github.com/netbirdio/netbird/iface"
+)
+
+// DefaultServer dummy dns server
+type DefaultServer struct {
+}
+
+// NewDefaultServer On Android the DNS feature is not supported yet
+func NewDefaultServer(ctx context.Context, wgInterface *iface.WGIface, customAddress string) (*DefaultServer, error) {
+	return &DefaultServer{}, nil
+}
+
+// Start dummy implementation
+func (s DefaultServer) Start() {
+
+}
+
+// Stop dummy implementation
+func (s DefaultServer) Stop() {
+
+}
+
+// UpdateDNSServer dummy implementation
+func (s DefaultServer) UpdateDNSServer(serial uint64, update nbdns.Config) error {
+	return nil
+}