Add admin page for experimental features

[MAILPOET-2008]

views/experimental-features.html

@@ -0,0 +1,24 @@
+<% extends 'layout.html' %>
+
+<% block content %>
+
+<div class="wrap">
+  <h1>Experimental features</h1>
+
+  <div class="mailpoet_notice notice notice-error">
+    <p>
+      <strong>These features are not finished, they are not meant to be used yet.</strong>
+    </p>
+    <p>
+      If you enable them anything can happen: your website may go down,
+      all your data can be deleted.
+    </p>
+    <p>
+      We are not liable.
+    </p>
+  </div>
+
+  <div id="experimental_features_container"></div>
+</div>
+
+<% endblock %>