Closes #11294: Markdown Preview (#11894)

* MarkdownWidget

* Change border and color of active markdown tab

* Fix template name typo

* Add render markdown endpoint

* Static assets for markdown widget

* widget style fix and unique ids based on name

* Replace SmallTextArea with SmallMarkdownWidget

* Clear innerHTML before swapping

* render markdown directly in template

* change render markdown view path

* remove small markdown widget

* Simplify rendering logic

* Use a form to clean input Markdown data

---------

Co-authored-by: Jeremy Stretch <jstretch@ns1.com>

netbox/utilities/forms/widgets.py

@@ -16,6 +16,7 @@ __all__ = (
     'ColorSelect',
     'DatePicker',
     'DateTimePicker',
+    'MarkdownWidget',
     'NumericArrayField',
     'SelectDurationWidget',
     'SelectSpeedWidget',
@@ -116,6 +117,10 @@ class SelectDurationWidget(forms.NumberInput):
     template_name = 'widgets/select_duration.html'
 
 
+class MarkdownWidget(forms.Textarea):
+    template_name = 'widgets/markdown_input.html'
+
+
 class NumericArrayField(SimpleArrayField):
 
     def clean(self, value):