[ADD] web: add widget button of Active/Deactive user.

[IMP] Improve user form view

- Task: https://www.odoo.com/web#id=7767&view_type=form&model=project.task&action=333&active_id=131
- Pad: https://pad.odoo.com/p/r.lFw6dVRQWxXWZUJk
This widget seems too specific to me. You should build a widget working on a boolean field, taking from options labels to display in a selection box and strings to display in confirm boxes (optional). So basically it stays the same, but can be configured from widget options.

In the current implementation there are issues, for example when hovering (the text becomes difficult to read). Probably some fixes to do here.