Refactor resource calendar and resource mixin:
- add a required timezone field on models 'resource.calendar' and 'resource.resource';
- resource calendar attendances are now computed in the timezone of the resource
or the calendar;
- improve API of 'resource.calendar' and 'resource.mixin';
- avoid other modules from using the implementation methods of 'resource.calendar';
- refactor implementation of 'resource.calendar' to make it more efficient.
It happens due to workcenter working hours,
the workcenter is not active during the weekend thus
the productivity loss are not counted in the oee.
This commit removes 2 days to the test date if it is
during the weekend.
Raphael Collet