Purpose of this commit is to simplify fields used in leave and allocation
used to store the duration of the requests. We want notably to get rid
of "number of days temp" that, contrary to its name, is not temporary
at all as it stores the real number of days. We also want to clarify
the hours or days encoding that is different on leave and allocation models.
Specifications
* number_of_days on leave and allocation is the master field holding the
leave or allocation duration in days;
* two fields are used for interface that are suffixed by _display in order
to indicate they are UX only: number_of_hours_display and number_of_days_
display. They are interface fields used for the user and correct number
of days is computed and stored in number_of_days;
* more specifically for leave model
* display fields are readonly as it is computed based on dates given by
the user, directly (from / to) or indirectly (half-day leaves for example);
* duration field is computed through an onchange. It could be directly
set by hand by managers if some confusion in the number of days appear;
* more specifically for allocation model
* display fields trigger an inverse as they are the real duration given
by HR officers or managers;
* duration field is computed through the inverse of display fields;
Various reports, data and use of leave / allocation models are updated to
use the correct field.
This commit is linked to task ID 1876795 and PR #26571.