build(aio): remove formatting and styles from dgeni templates

Much of the formatting was hardcoded and copied from the old anguar.io
jade files. This gives us a clean start.

Also, more use has been made of include files to make the templates
easier to understand and manage.

docs/templates/includes/_inputs.html

@@ -0,0 +1,13 @@
+{% if doc.inputs %}
+<section class="inputs">
+  <h2>Inputs</h2>
+  <div class="description">
+    {% for binding, property in doc.inputs %}
+    <div class="input">
+      <code>{$ property.bindingName $}</code>&nbsp;bound to&nbsp;<code>{$ property.memberDoc.classDoc.name $}.{$ property.propertyName $}</code>
+      {$ property.memberDoc.description | trimBlankLines | marked $}
+    </div>
+    {% endfor %}
+  </div>
+</section>
+{% endif %}