Added views for part and part category

- Worked out simple linking
- Category path displaying correctly
- Category page lists parts in category

InvenTree/part/templates/part/category.html

@@ -0,0 +1,17 @@
+<h1>Category: {{ category.name }}</h1>
+
+<h2>Path: {{ category }}</h2>
+
+<br>
+Path<br>
+
+{# Construct the category path #}
+{% for path_item in category.path %}
+<a href="../{{path_item.pk}}">{{path_item.name}}</a>/
+{% endfor %}
+
+<br>Parts:<br>
+
+{% for part in category.part_set.all %}
+<a href="/part/{{part.pk}}">{{part.name}}</a><br>
+{% endfor %}

InvenTree/part/templates/part/detail.html

@@ -0,0 +1 @@
+{{part}}