caddytls: verifier: caddyfile: re-add Caddyfile support (#6127)

* caddytls: verifier: caddyfile: re-add Caddyfile support

* appease the linter

* caddytls: client_auth: verifier: change namespace to `tls.client_auth.verifier`

internal/testmocks/dummyverifier.go

@@ -0,0 +1,41 @@
+package testmocks
+
+import (
+	"crypto/x509"
+
+	"github.com/caddyserver/caddy/v2"
+	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
+	"github.com/caddyserver/caddy/v2/modules/caddytls"
+)
+
+func init() {
+	caddy.RegisterModule(new(dummyVerifier))
+}
+
+type dummyVerifier struct{}
+
+// UnmarshalCaddyfile implements caddyfile.Unmarshaler.
+func (dummyVerifier) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
+	return nil
+}
+
+// CaddyModule implements caddy.Module.
+func (dummyVerifier) CaddyModule() caddy.ModuleInfo {
+	return caddy.ModuleInfo{
+		ID: "tls.client_auth.verifier.dummy",
+		New: func() caddy.Module {
+			return new(dummyVerifier)
+		},
+	}
+}
+
+// VerifyClientCertificate implements ClientCertificateVerifier.
+func (dummyVerifier) VerifyClientCertificate(rawCerts [][]byte, verifiedChains [][]*x509.Certificate) error {
+	return nil
+}
+
+var (
+	_ caddy.Module                       = dummyVerifier{}
+	_ caddytls.ClientCertificateVerifier = dummyVerifier{}
+	_ caddyfile.Unmarshaler              = dummyVerifier{}
+)