8927 plugin search (#10489)

* #7016 base search classes

* 7016 add search indexes

* 7016 add search indexes

* 7016 add search indexes

* 7016 add search indexes

* 7016 add search indexes

* 7016 add search indexes

* 8927 refactor search

* 8927 refactor search

* 8927 refactor search

* 8927 refactor search

* 8927 get search choices working

* 8927 cleanup - optimize

* 8927 use backend search function

* 8927 fix for plugin search

* 8927 add docs

* Move search app to a module under netbox/

* Utilize global registry to register model search classes

* Build search form options from registry

* Determine search categories from model app by default

* Enable dynamic search registration for plugins

* Update docs & improve plugin support

* Clean up search backend class

* Docs for #8927

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

docs/plugins/development/search.md

@@ -0,0 +1,29 @@
+# Search
+
+Plugins can define and register their own models to extend NetBox's core search functionality. Typically, a plugin will include a file named `search.py`, which holds all search indexes for its models (see the example below).
+
+```python
+# search.py
+from netbox.search import SearchMixin
+from .filters import MyModelFilterSet
+from .tables import MyModelTable
+from .models import MyModel
+
+class MyModelIndex(SearchMixin):
+    model = MyModel
+    queryset = MyModel.objects.all()
+    filterset = MyModelFilterSet
+    table = MyModelTable
+    url = 'plugins:myplugin:mymodel_list'
+```
+
+To register one or more indexes with NetBox, define a list named `indexes` at the end of this file:
+
+```python
+indexes = [MyModelIndex]
+```
+
+!!! tip
+    The path to the list of search indexes can be modified by setting `search_indexes` in the PluginConfig instance.
+
+::: netbox.search.SearchIndex