Rudder

We need some way to let the user choose in what mode Rudder works.

At first, it will be a global switch and all nodes will be in the same mode. In the future, each node could be in either compliance or error only mode.

That mode will:
- have an effect on the generated promises so that then know if they have to log success or not,
- have an effect on Rudder display to let the user knows that compliance assessment is disabled,
- have an effect on the logic that get execution reports and display them to the user/api/etc.

The parameter value will be store in LDAP.

That ticket is ONLY for the UI and storing of the parameter.