[IMP] project: default company of a task

In Project app, we now ensure the company of a task. Indeed, since that
model can be billed, and is important in some business, we need to ensure
its link to a company. A task can live outside a project, so the company
of a task can not be related. Task company can be set by user, but must
be the same as the project (is set), as the task can be billed depending
on project properties.

Task-1999686