This commit adds a feature that allows users to request periods of inactivity from their managers. This is effectively known as a leave of absence.
The commit also introduces new permissions and migrations, therefore, you'll need to adapt your database according to these changes.
This commit fixes the appointment policy being called at the wrong time, with the wrong arguments.
It also fixes wrong references on the auth service provider, also fixing other issues with poliy usage.
Fixes#3 and SPACEJEWEL-HOSTING-59.
