Remove coin:policy_enforcement_decision_required checkbox

[baszoetekouw]

As PDP policies are now administered in Manage, it doesn't really make sense to check or uncheck the coin:policy_enforcement_decision_required metadata field manually. Rather, it should be automatically set by Manage if PDP policies are present for this entity (and unset if PDP policies are removed).

There are two possibilities:

• remove the checkbox from the gui altogether and automatically send coin:policy_enforcement_decision_required in the push of PDP policies are present
• make the checkbox in the gui readonly and let Manage set or unset the value of the checkbox when PDP polcies are added or removed.

I'm not sure which of the two is the best solution.
The first one is probably easier to implement and sounds a bit cleaner, but the second one is more transparent and allows the user to check what is happening.

In both cases though we are adding more business logic to Manage; I think that's unavoidable if we want to automate more of the support, but we should be careful how we implement these things. Maybe we can make such automations more generic and make them configurable in some way, so that the feature is more generally useful and rules like this don't get scattered around the code.