proxy: add userinfo and webauthn endpoints (#3755)

* proxy: add userinfo and webauthn endpoints

* use TLD for RP id

* use EffectiveTLDPlusOne

* upgrade webauthn

* fix test

* Update internal/handlers/jwks.go

Co-authored-by: bobby <1544881+desimone@users.noreply.github.com>

Co-authored-by: bobby <1544881+desimone@users.noreply.github.com>

pkg/webauthnutil/webauthnutil_test.go

@@ -0,0 +1,31 @@
+package webauthnutil
+
+import (
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetEffectiveDomain(t *testing.T) {
+	t.Parallel()
+	for _, tc := range []struct {
+		in     string
+		expect string
+	}{
+		{"https://www.example.com/some/path", "example.com"},
+		{"https://www.example.com:8080/some/path", "example.com"},
+		{"https://www.subdomain.example.com/some/path", "example.com"},
+		{"https://example.com/some/path", "example.com"},
+	} {
+		tc := tc
+		t.Run(tc.expect, func(t *testing.T) {
+			t.Parallel()
+
+			r, err := http.NewRequest(http.MethodGet, tc.in, nil)
+			require.NoError(t, err)
+			assert.Equal(t, tc.expect, GetEffectiveDomain(r))
+		})
+	}
+}