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>

templates/base_assets.html

@@ -1,4 +1,9 @@
 {% extends 'base.html' %}
+
+{% block extrahead %}
+<meta name="google" content="notranslate">
+{% endblock %}
+
 {% block titleheader %}
     <a class="nav navbar-brand navbar-left" href="/"><i class="glyphicon glyphicon-circle-arrow-left" style="vertical-align: middle !important;"></i> RIGS</a>
     <a class="nav navbar-brand" href="{% url 'asset_index' %}">Assets</a>