Before this commit, when a project user shares a recurrent task to an
internal user, the internal user cannot open the form view of that task
because he does not have access to `project.task.recurrence` model.
The reason is because the compute methods to set the recurrence fields
assumed the user has access to that model.
This commit adds `groups="project.project_group_user"` to recurrent fields
to be sure the user has access to `project.task.recurrence` model before
computing the field.
task-3430762
closesodoo/odoo#148636
X-original-commit: c1623c7c8b1a3c5c69a866b55db77e69958e8754
Related: odoo/enterprise#53911
Signed-off-by: Xavier Bol (xbo) <xbo@odoo.com>