[MOV] web, website: move navbar-mobile logic to website

Since the framework's navbar uses the hamburger_menu in community too,
the `navbar_mobile.scss` code initially shared between frontend and
backend is now needed for the frontend only.

This commit is part of v16 overall restyle (task-2704984).

task-2712151

Part-of: odoo/odoo#82434

addons/web/__manifest__.py

@@ -224,7 +224,6 @@ This module provides the core of the Odoo Web Client.
 
             'web/static/src/legacy/scss/base_frontend.scss',
             'web/static/src/legacy/scss/lazyloader.scss',
-            'web/static/src/legacy/scss/navbar_mobile.scss',
 
             ('include', 'web.assets_frontend_minimal'),
 

addons/website/__manifest__.py

@@ -123,6 +123,7 @@
             'website/static/src/scss/website.scss',
             'website/static/src/scss/website.ui.scss',
             'website/static/src/scss/website.navbar.scss',
+            'website/static/src/scss/website.navbar.mobile.scss',
             'website/static/src/js/utils.js',
             'website/static/src/js/content/website_root.js',
             'website/static/src/js/widgets/dialog.js',