Purpose
=======
The main definition of 'assignation' is the following:
"an appointment to meet someone in secret, typically one made by lovers"
The correct word we should be using is 'assignment':
"the allocation of someone or something as belonging to a particular group or category"
So in this commit change every iteration of the word
'assignation' to 'assignment', across all modules.
closes odoo/odoo#45041
Taskid: 1966215
Closes: #45041
Related: odoo/enterprise#8375
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>