Added ability to edit parts

- installed django_crispy_forms
- added EditPartForm in part/forms.py
- Vastly simplified parts views by using class views 
  (need to do this for the other apps too!)

InvenTree/part/templates/part/delete.html

@@ -0,0 +1,2 @@
+{% extends 'part/part_base.html' %}
+

InvenTree/part/templates/part/detail.html

@@ -6,5 +6,10 @@
 
 
 Part details go here...
+<br>
+
+<a href="{% url 'part-edit' part.id %}"><button class="btn btn-info">Edit Part</button></a>
+
+<a href="{% url 'part-delete' part.id %}"><button class="btn btn-danger">Delete Part</button></a>
 
 {% endblock %}

InvenTree/part/templates/part/edit.html

@@ -0,0 +1,11 @@
+{% extends "part/part_base.html" %}
+
+{% block details %}
+
+Edit part information:
+
+{% load crispy_forms_tags %}
+
+{% crispy form %}
+
+{% endblock %}