Change brand color and logotypes (#18592)

- Add rake task for generating Apple/Android icons and favicons from SVG
- Add rake task for generating PNG icons and logos for e-mails from SVG
- Remove obsolete Microsoft icons and configuration
- Remove PWA shortcut icons

app/views/layouts/embedded.html.haml

@@ -21,4 +21,4 @@
     = yield
 
     .logo-resources
-      = raw render file: Rails.root.join('app', 'javascript', 'images', 'logo_transparent.svg')
+      = render_symbol :icon