Frontend refactor (#1471)

Refactor Frontend + Asset code

- Use Laravel's Filesystem component for asset IO, meaning theoretically
  assets should be storable on S3 etc.

- More reliable checking for asset recompilation when debug mode is on,
  so you don't have to constantly delete the compiled assets to force
  a recompile. Should also fix issues with locale JS files being
  recompiled with the same name and cached.

- Remove JavaScript minification, because it will be done by Webpack
  (exception is for the TextFormatter JS).

- Add support for JS sourcemaps.

- Separate frontend view and assets completely. This is an important
  distinction because frontend assets are compiled independent of a
  request, whereas putting together a view depends on a request.

- Bind frontend view/asset factory instances to the container (in
  service providers) rather than subclassing. Asset and content
  populators can be added to these factories – these are simply objects
  that populate the asset compilers or the view with information.

- Add RouteHandlerFactory functions that make it easy to hook up a
  frontend controller with a frontend instance ± some content.

- Remove the need for "nojs"

- Fix cache:clear command

- Recompile assets when settings/enabled extensions change

views/frontend/forum.blade.php

@@ -1,64 +1,42 @@
-<?php
-/**
- * Forum Web App Template
- *
- * NOTE: You shouldn't edit this file directly. Your changes will be overwritten
- * when you update Flarum. See flarum.org/docs/templates to learn how to
- * customize your forum's layout.
- *
- * Flarum's JavaScript app mounts various components into key elements in
- * this template. They are distinguished by their ID attributes:
- *
- * - #app
- * - #app-navigation
- * - #drawer
- * - #header
- * - #header-navigation
- * - #home-link
- * - #header-primary
- * - #header-secondary
- * - #content
- * - #composer
- */
-?>
-{!! array_get($forum, 'attributes.headerHtml') !!}
+{!! array_get($forum, 'headerHtml') !!}
 
 <div id="app" class="App">
 
-  <div id="app-navigation" class="App-navigation"></div>
+    <div id="app-navigation" class="App-navigation"></div>
 
-  <div id="drawer" class="App-drawer">
+    <div id="drawer" class="App-drawer">
 
-    <header id="header" class="App-header">
-      <div id="header-navigation" class="Header-navigation"></div>
-      <div class="container">
-        <h1 class="Header-title">
-          <a href="{{ array_get($forum, 'attributes.baseUrl') }}" id="home-link">
-            <?php $title = array_get($forum, 'attributes.title'); ?>
-            @if ($logo = array_get($forum, 'attributes.logoUrl'))
-              <img src="{{ $logo }}" alt="{{ $title }}" class="Header-logo">
-            @else
-              {{ $title }}
-            @endif
-          </a>
-        </h1>
-        <div id="header-primary" class="Header-primary"></div>
-        <div id="header-secondary" class="Header-secondary"></div>
-      </div>
-    </header>
+        <header id="header" class="App-header">
+            <div id="header-navigation" class="Header-navigation"></div>
+            <div class="container">
+                <h1 class="Header-title">
+                    <a href="{{ array_get($forum, 'baseUrl') }}" id="home-link">
+                        @if ($logo = array_get($forum, 'logoUrl'))
+                            <img src="{{ $logo }}" alt="{{ array_get($forum, 'title') }}" class="Header-logo">
+                        @else
+                            {{ array_get($forum, 'title') }}
+                        @endif
+                    </a>
+                </h1>
+                <div id="header-primary" class="Header-primary"></div>
+                <div id="header-secondary" class="Header-secondary"></div>
+            </div>
+        </header>
 
-  </div>
-
-  <main class="App-content">
-    <div id="content"></div>
-
-    {!! $content !!}
-
-    <div class="App-composer">
-      <div class="container">
-        <div id="composer"></div>
-      </div>
     </div>
-  </main>
+
+    <main class="App-content">
+        <div id="content"></div>
+
+        {!! $content !!}
+
+        <div class="App-composer">
+            <div class="container">
+                <div id="composer"></div>
+            </div>
+        </div>
+    </main>
 
 </div>
+
+{!! array_get($forum, 'footerHtml') !!}