[WIP] Testable parts (#7888)

* Add "testable" field to the Part model

- Default = False
- Determines whether a particular part can have tests defined against it

* Adds data migration to set default 'testable' state

* Update part serializers

* CUI: Update table filters

* PUI: Update tables and filters

* CUI: Update part detail page

* PUI: Update part detail page

* Update CUI

* Update build pages

* Update BuildLine serializer

* Bump API version

* Update docs

* Add 'testable' to fieldset

src/frontend/src/functions/icons.tsx

@@ -129,6 +129,7 @@ const icons = {
   shipment: IconTruckDelivery,
   scheduling: IconCalendarStats,
   test_templates: IconTestPipe,
+  test: IconTestPipe,
   related_parts: IconLayersLinked,
   attachments: IconPaperclip,
   note: IconNotes,