Add Metadata to further models (#4410)

* Add metadata for ManufacturerPart

* Add Metadata for SupplierPart

* Add metadata to label models

* Add metadata to order line items

* Add metadata to shipment

* Add metadata to Build and BuildItem

* Add metadata to BomItem

* Add metadata to PartParameterTemplate

* Syntax, lint

* Fix isort style

* Lint

* Correction of model name

* Metadata for Reports

* Fix silly error

* Fix silly error

* Correct model name

* Correct model name

* Correction

* Correct company urls

* Apply generic model to Report metadat

* Rename/remove redundant import

* Remove shadowing of report in loop variable

* Update import ordering

* More corrections

* better docstrings

* Correct names for API endpoints

* Default to PO, required for api-doc to work

* Changes by @matmair

* Suppress metadata from Bom export

* Add migration files

* Increment API version

* Add tests for all Metadata models, even previously existing ones

* Update tests

* Fix

* Delay tests

* Fix imports

* Fix tests

* API Version number

* Remove unused import

* isort

* Revent  unintended change of cache

InvenTree/part/admin.py

@@ -318,7 +318,7 @@ class BomItemResource(InvenTreeResource):
         is_importing = getattr(self, 'is_importing', False)
         include_pricing = getattr(self, 'include_pricing', False)
 
-        to_remove = []
+        to_remove = ['metadata']
 
         if is_importing or not include_pricing:
             # Remove pricing fields in this instance