Closes #11558: Add support for remote data sources (#11646)

* WIP

* WIP

* Add git sync

* Fix file hashing

* Add last_synced to DataSource

* Build out UI & API resources

* Add status field to DataSource

* Add UI control to sync data source

* Add API endpoint to sync data sources

* Fix display of DataSource job results

* DataSource password should be write-only

* General cleanup

* Add data file UI view

* Punt on HTTP, FTP support for now

* Add DataSource URL validation

* Add HTTP proxy support to git fetcher

* Add management command to sync data sources

* DataFile REST API endpoints should be read-only

* Refactor fetch methods into backend classes

* Replace auth & git branch fields with general-purpose parameters

* Fix last_synced time

* Render discrete form fields for backend parameters

* Enable dynamic edit form for DataSource

* Register DataBackend classes in application registry

* Add search indexers for DataSource, DataFile

* Add single & bulk delete views for DataFile

* Add model documentation

* Convert DataSource to a primary model

* Introduce pre_sync & post_sync signals

* Clean up migrations

* Rename url to source_url

* Clean up filtersets

* Add API & filterset tests

* Add view tests

* Add initSelect() to HTMX refresh handler

* Render DataSourceForm fieldsets dynamically

* Update compiled static resources

netbox/core/search.py

@@ -0,0 +1,21 @@
+from netbox.search import SearchIndex, register_search
+from . import models
+
+
+@register_search
+class DataSourceIndex(SearchIndex):
+    model = models.DataSource
+    fields = (
+        ('name', 100),
+        ('source_url', 300),
+        ('description', 500),
+        ('comments', 5000),
+    )
+
+
+@register_search
+class DataFileIndex(SearchIndex):
+    model = models.DataFile
+    fields = (
+        ('path', 200),
+    )