feat: Add support for flyout menu mode in MegaMenu

- Introduced `MegaMenuMode` type and `normalizeMegaMenuMode` function to handle menu modes.
- Updated `MegaMenuApplicationCustomizer` to accept `menuMode` property.
- Enhanced `MegaMenuRenderer` to render flyout menus based on the selected mode.
- Created new HTML previews for both flyout and mega menu modes.
- Removed unused mock services and user custom action service interfaces.

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "mega-menu",
-  "version": "2.0.1",
+  "version": "2.1.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {