refactor fileupload in dashboard & storage-index (#153 & #154).

I've kept the old versions commented out for now until I'm comfortable I've not
missed an obvious edge-case.

templates/dashboard.html

@@ -21,24 +21,25 @@
         </p>
 </div>
 
-<form action="/storage/multi-upload"
-      method="POST"
-      enctype="multipart/form-data">
-    <input required
-	   type="hidden"
-	   name="AUTHENTICITY-TOKEN"
-	   value="{{token}}">
-    <input required
-	   type="file"
-	   name="STORAGE-FILES"
-	   multiple>
-    <button class="be-gui-button-no-text"
-	    title="Click to upload files to storage"
-	    type="submit">
-	<img alt="Upload to Storage"
-	     src="/images/icons/up-arrow.png">
-    </button>
-</form>
+<!-- <form action="/storage/multi-upload" -->
+<!--       method="POST" -->
+<!--       enctype="multipart/form-data"> -->
+<!--     <input required -->
+<!-- 	   type="hidden" -->
+<!-- 	   name="AUTHENTICITY-TOKEN" -->
+<!-- 	   value="{{token}}"> -->
+<!--     <input required -->
+<!-- 	   type="file" -->
+<!-- 	   name="STORAGE-FILES" -->
+<!-- 	   multiple> -->
+<!--     <button class="be-gui-button-no-text" -->
+<!-- 	    title="Click to upload files to storage" -->
+<!-- 	    type="submit"> -->
+<!-- 	<img alt="Upload to Storage" -->
+<!-- 	     src="/images/icons/up-arrow.png"> -->
+<!--     </button> -->
+  <!-- </form> -->
+{% include "layouts/storage-multiupload.html" %}
 {% endif %}
 
 <ul>

templates/storage-index.html

@@ -3,24 +3,26 @@
 {% block content %}
 <h2>Storage</h2>
 
-<form action="/storage/multi-upload"
-      method="POST"
-      enctype="multipart/form-data">
-    <input required
-	   type="hidden"
-	   name="AUTHENTICITY-TOKEN"
-	   value="{{token}}">
-    <input required
-	   type="file"
-	   name="STORAGE-FILES"
-	   multiple>
-    <button class="be-gui-button-no-text"
-	    title="Click to upload files to storage"
-	    type="submit">
-	<img alt="Upload to Storage"
-	     src="/images/icons/up-arrow.png">
-    </button>
-</form>
+<!-- <form action="/storage/multi-upload" -->
+<!--       method="POST" -->
+<!--       enctype="multipart/form-data"> -->
+<!--     <input required -->
+<!-- 	   type="hidden" -->
+<!-- 	   name="AUTHENTICITY-TOKEN" -->
+<!-- 	   value="{{token}}"> -->
+<!--     <input required -->
+<!-- 	   type="file" -->
+<!-- 	   name="STORAGE-FILES" -->
+<!-- 	   multiple> -->
+<!--     <button class="be-gui-button-no-text" -->
+<!-- 	    title="Click to upload files to storage" -->
+<!-- 	    type="submit"> -->
+<!-- 	<img alt="Upload to Storage" -->
+<!-- 	     src="/images/icons/up-arrow.png"> -->
+<!--     </button> -->
+<!-- </form> -->
+
+{% include "layouts/storage-multiupload.html" %}
 
 <input type="text"
        id="search-filter"