Feature: Supplier part pack size (#3644)

* Adds 'pack_size' field to SupplierPart model

* Edit pack_size for SupplierPart via API

* Display pack size in supplier part page template

* Improve table ordering for SupplierPart table

* Fix for API filtering

- Need to use custom filter class

* Adds functionality to duplicate an existing SupplierPart

* Bump API version number

* Display annotation of pack size in purchase order line item table

* Display additional information in part purchase order table

* Add UOM to purchase order table

* Improve receive items functionality

* Indicate quantity which will be received in modal form

* Update the received quantity as the user changes the value

* Take  the pack_size into account when receiving line items

* Take supplierpart pack size into account when receiving line items

* Add "pack size" column to purchase order line item table

* Tweak supplier part table

* Update 'on_order' queryset annotation to take pack_size into account

- May god have mercy on my soul

* Adds a unit test to validate that the on_order queryset annotation is working as expected

* Update Part.on_order method to take pack_size into account

- Check in existing unit test also

* Fix existing unit tests

- Previous unit test was actually in error
- Logic for calculating "on_order" was broked

* More unit tests for receiving items against a purchase order

* Allow pack_size < 1

* Display pack size when adding / editing PurchaseOrderLineItem

* Fix bug in part purchase order table

* Update part purchase order table again

* Exclude notificationmessage when exporting dataset

* Also display pack size when ordering parts from secondary form

* javascript linting

* Change user facing strings to "Pack Quantity"

tasks.py

@@ -43,6 +43,7 @@ def content_excludes():
         "exchange.rate",
         "exchange.exchangebackend",
         "common.notificationentry",
+        "common.notificationmessage",
         "user_sessions.session",
     ]