This commit adds methods to easily obtain calendar validity per resource
for a given search period and get the work intervals per resource,
taking into account the validity of their calendars.
In hr, the create and departure date of an employee are taken into
account to compute the calendars validity.
In hr_contract, it looks for every contract of human resources with
employee of type student or employee existing in the search period and
consider the specific calendar of the contract as valid during the
contract-lifetime.
PR: #77362
task-2646630
Before this commit, It was not possible to copy An employee which is already linked to User due `user_uniq` constraints.
Now we add `copy=False` on `user_id` field, so Employee will be copied without linked User.
closesodoo/odoo#49915
X-original-commit: 2a63df03859166414be338c6655ee8c4052666b7
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>
Thibault Libioulle