Closes #11559: Implement config template rendering (#11769)

* WIP

* Add config_template field to Device

* Pre-fetch referenced templates

* Correct up_to_date callable

* Add config_template FK to Device

* Update & merge migrations

* Add config_template FK to Platform

* Add tagging support for ConfigTemplate

* Catch exceptions when rendering device templates in UI

* Refactor ConfigTemplate.render()

* Add support for returning plain text content

* Add ConfigTemplate model documentation

* Add feature documentation for config rendering

netbox/extras/forms/bulk_import.py

@@ -10,6 +10,7 @@ from extras.utils import FeatureQuery
 from utilities.forms import CSVChoiceField, CSVContentTypeField, CSVModelForm, CSVMultipleContentTypeField, SlugField
 
 __all__ = (
+    'ConfigTemplateImportForm',
     'CustomFieldImportForm',
     'CustomLinkImportForm',
     'ExportTemplateImportForm',
@@ -83,6 +84,15 @@ class ExportTemplateImportForm(CSVModelForm):
         )
 
 
+class ConfigTemplateImportForm(CSVModelForm):
+
+    class Meta:
+        model = ConfigTemplate
+        fields = (
+            'name', 'description', 'environment_params', 'template_code', 'tags',
+        )
+
+
 class SavedFilterImportForm(CSVModelForm):
     content_types = CSVMultipleContentTypeField(
         queryset=ContentType.objects.all(),