Add Options, Functions and Settings to convert Node-Names and Strings to kebab-case

- refactored and renamed String::_camelcase_to_underscore to String:_separate_compound_words
- refactored String::to_snake_case to work with the refactored String::_separate_compound_words
- created char_utils::is_hyphen to catch all hyphen variants in kebab-case conversion
- created String::to_kebab_case using the new String::_separate_compound_words
- created corresponding Documentation in String and StringName
- simplified both switch statements in EditorNode and ProjectDialog
- added new kebab-casing Option for Node Names in ProjectSettings
- added missing camelCase Options to Scene- and Node-Names in ProjectSettings
- simplified Mono RuntimeInterop Functions
- hooked up the ConnectionsDialog
- created additional Unit Tests

editor/project_manager/project_dialog.cpp

@@ -277,7 +277,7 @@ void ProjectDialog::_update_target_auto_dir() {
 		case 0: // No convention
 			break;
 		case 1: // kebab-case
-			new_auto_dir = new_auto_dir.to_lower().replace_char(' ', '-');
+			new_auto_dir = new_auto_dir.to_kebab_case();
 			break;
 		case 2: // snake_case
 			new_auto_dir = new_auto_dir.to_snake_case();