fix(agent): reduce the size of agent binary by modules separation

internal/dnsproviders/dummy.go

@@ -0,0 +1,20 @@
+package dnsproviders
+
+type DummyConfig struct{}
+type DummyProvider struct{}
+
+func NewDummyDefaultConfig() *DummyConfig {
+	return &DummyConfig{}
+}
+
+func NewDummyDNSProviderConfig(*DummyConfig) (*DummyProvider, error) {
+	return &DummyProvider{}, nil
+}
+
+func (DummyProvider) Present(domain, token, keyAuth string) error {
+	return nil
+}
+
+func (DummyProvider) CleanUp(domain, token, keyAuth string) error {
+	return nil
+}