Smarter approach to the cookies (#103)

* Smarter approach to the cookies

  - Single maxCookieSize = 1400 constant with clear documentation
  - Combined cookie storage for ~40-45% size reduction
  - Backward compatible migration from legacy cookies

* Tuneup the code.

main_initialization_test.go

@@ -15,10 +15,10 @@ import (
 // TestInitializeMetadata tests the initializeMetadata function
 func TestInitializeMetadata(t *testing.T) {
 	tests := []struct {
-		name         string
-		providerURL  string
 		setupMock    func() *httptest.Server
 		validateFunc func(*testing.T, *TraefikOidc)
+		name         string
+		providerURL  string
 		wantPanic    bool
 	}{
 		{