added invalidity hints to item side-properties

- added :invalid definition to side-properties CSS
-  defined common color for invalidity
- now using disabled input for automatically calculated properties

src/templates/item/partials/description.hbs

@@ -20,10 +20,10 @@
             <input type="text" data-dtype="String" name="data.storageLocation" value="{{data.storageLocation}}" />
         </div>
         {{else}}
-        {{localize "DS4.NotOwned"}}
+        <span>{{localize "DS4.NotOwned"}}</span>
         {{/if}}
     </div>
-    <div class="description">
+    <div class="description" title="{{localize 'DS4.Description'}}">
         {{editor content=data.description target="data.description" button=true owner=owner editable=editable}}
     </div>
 </div>