Invoices can now group tax lines, making it easier to show and manage retained taxes on reports. This improves tax reporting clarity, including support for Colombian localization needs.

Task => https://www.odoo.com/web#id=20051&view_type=form&model=project.task&action=333&active_id=708

This PR fixes one issue and introduces tax groups to enable retention of taxes i.e. enables to split tax lines by group on invoice report

This adds a new timesheet synchronization module with an HTML app that can also be packaged as a Chrome extension or Android app. It helps users manage timesheets outside the standard interface and improves reliability by detecting missing server support and showing clearer messages.