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.json

@@ -1,16 +1,17 @@
 {
   "name": "mega-menu",
-  "version": "2.0.1",
+  "version": "2.1.0",
   "private": true,
   "main": "lib/index.js",
   "engines": {
     "node": ">=6.9.0 <9.0.0"
   },
   "scripts": {
-    "build": "gulp bundle",
+    "build:classic": "powershell -NoProfile -ExecutionPolicy Bypass -File .\\build-classic.ps1",
+    "build": "npm run build:classic && gulp bundle",
     "clean": "gulp clean",
     "test": "gulp test",
-    "package": "gulp clean && gulp bundle --ship && gulp package-solution --ship"
+    "package": "npm run build:classic && gulp clean && gulp bundle --ship && gulp package-solution --ship"
   },
   "dependencies": {
     "@microsoft/decorators": "~1.4.1",