[IMP] hr_timesheet: hide the "Round timesheets" feature in the settings of...

[IMP] hr_timesheet: hide the "Round timesheets" feature in the settings of Timesheets if encoding unit is Days

[IMP] hr_timesheet: hide the "Timesheet Timer" feature in the project form if encoding unit is not Hours

[IMP] hr_timesheet: clean display of Days for timesheets

A computed field has to be added to retrieve the encoding uom of the current company and be used in the views.
FieldTimesheetFactor field has to be registered to "float_factor" widget for the "planned_hours" field to work correctly with Days
(for the conversion from hours to days to be computed and to be able to set a greater value than 1 day)

If encoding unit for timesheets is set to Days:
- Display Days instead of Hours in Portal > Timesheets
- Display Days instead of Hours in Portal > Tasks
- Display Days instead of Hours in Portal > Invoices & Bills
- Display Days instead of Hours in Portal > Tickets

[IMP] hr_timesheet: display clean duration in Timesheet Entries

Display Days instead of Hours in Timesheet Entries (print action) if encoding unit for timesheets is set to Days

[IMP] hr_timesheet: correctly display timesheets in Days if configured to

- correctly display remaining days in project.task kanban and list view
- hide timer start button if timesheet is configured in Days
- update several column names

[IMP] hr_timesheet: clean code

[IMP] hr_timesheet: small improvements when displaying timesheets in days

- Rename some labels
- Fixes style
- Prevent fields displayed with widget "timesheet_uom" to change when timer is on
- Display correctly "Initially Planned Days" field in task creation form