[IMP] Improve stock's barcode start page

remove module_boot() usage
[IMP] changed barcode start page url to /stock/barcode

As a convention we use the module name as first fragment of the url
Merge pull request #1209 from odoo-dev/master-stock-fme

[IMP] Improve stock's barcode start page

- Created a template for the start page
- Removed now useless call to module_boot()
- Changed url to /stock/barcode