Refactor the web app bootstrapping code

- All custom JS variables are now preloaded into the `app.data` object, rather than directly on the `app` object. This means that admin settings are available in `app.data.settings` rather than `app.settings`, etc.
- Cleaner route handler generation
- Renamed ConfigureClientView to ConfigureWebApp, though the former still exists and is deprecated
- Partial fix for #881 (strips ?nojs=1 from URL if possible, so that refreshing will attempt to load JS version again)

views/admin.blade.php

@@ -8,8 +8,8 @@
       <div id="header-navigation" class="Header-navigation"></div>
       <div class="container">
         <h1 class="Header-title">
-          <a href="{{ $forum->attributes->baseUrl }}">
-            {{ $forum->attributes->title }}
+          <a href="{{ array_get($forum, 'attributes.baseUrl') }}">
+            {{ array_get($forum, 'attributes.title') }}
           </a>
         </h1>
         <div id="header-primary" class="Header-primary"></div>