[14.0][ADD] hr_timesheet_sheet_save_tab

[hbrunn]

This module improves the UX of hr_timesheet_sheet by saving the timesheet form every time the user changes tabs. Without this, you'll lose data if you first change values in the summary tab, and then go to the details tab to adjust them without saving in between.

I've implemented this in a separate module because it might have unwanted side effects on integration code.

For Odoo versions >= 16.0, I think we should refactor the base module to show the same field on both tabs, then we won't have this problem any more.

[github-actions[bot]]

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