Generate Barcodes for Stock Locations

This module adds barcode generation to stock locations. On the stock location form you get a new "Barcode" group where you can pick a barcode rule (only rules set up for stock locations are offered), choose how the barcode base is defined, and then create the barcode.

• If the rule uses a manual base, you type the base yourself.
• If the rule uses a sequence, a "Generate Base (Using Sequence)" button fills the base automatically, and the base field becomes read-only.
• Once a rule and a base are present, a "Generate Barcode" button creates the final barcode and stores it on the location.

The barcode field is placed on the location form automatically, so it appears even if another module did not already add it. Access to these fields and buttons is limited to users in the barcode generation group.

The module also extends barcode rules so that "Stock Location" becomes a possible target model, meaning a rule can be dedicated to locations. When the module is uninstalled, barcode rules that were set up for stock locations are removed because they are no longer useful.

It works together with the stock location model and the barcode rule model, and relies on the shared barcode generation mixin for the actual generation logic.