[ADD] barcode_scanner: scanner-first Barcode app core

[szalatyzuzanna]

barcode_scanner — base framework of the Barcode suite

This PR adds barcode_scanner, the base module and first contribution to OCA/barcode-interface. It's the framework the rest of the Barcode suite builds on; feature modules (warehouse operations, GS1, device camera, inventory counts, purchase…) will follow in their own PRs on top of this base.

What it does

barcode_scanner ships no business logic of its own. It's a full-screen scanning application shell that other modules extend, the same way Odoo widgets self-register:

• a full-screen client action + lightweight in-app router;
• registries for screens, scan handlers and home-screen tiles
  (barcode_screens, barcode_scan_handlers, barcode_menu_tiles);
• the barcode input service (hardware / keyboard-wedge), audio & vibration
  feedback, an ORM/API wrapper and shared hooks.

As the base framework it has no end-user screens of its own: the feature modules that plug into these registries provide the actual operations, and land in follow-up PRs.

Developed and maintained by @BinhexTeam.

[jelenapoblet]

In prod with several clients.