Miscellaneous changes to the Asset DB (#390)

* FIX #388: Prevent assets losing supplier data on edit

* FEAT: Add associated assets to supplier detail view

* FIX: Tweak supplier list to make detail view accessible

* Potential fix for #380

No idea if it works because I can't reproduce locally. S/O Reckons it should... :P

* FEAT #386: Asset search searches serial number.

Pending addition of advanced search.

* FIX: Order asset categories/statuses alphabetically

Instead of by pk because that's silly.

* FEAT: Statuses can have a CSS class defined in the admin panel

This replaces the hardcoding of colours in the asset list.

* FIX: Squash migrations

* Fixed supplier not working on all the create asset template

* Refactored away "assets" property on "Supplier" by using "related_name" instead

Co-authored-by: Matthew Smith <mattysmith22@googlemail.com>

assets/templates/supplier_list.html

@@ -30,8 +30,8 @@
     <tr>
       <td>{{ item.name }}</td>
       <td>
+        <a href="{% url 'supplier_detail' item.pk %}" class="btn btn-default"><i class="glyphicon glyphicon-eye-open"></i> View</a>
         <a href="{% url 'supplier_update' item.pk %}" class="btn btn-default"><i class="glyphicon glyphicon-edit"></i> Edit</a>
-        <a href="{% url 'supplier_history' item.pk %}" class="btn btn-default"><i class="glyphicon glyphicon-time"></i> History</a>
       </td>
     </tr>
     {% endfor %}