Default whitelisting of tolerations (for taints)

Issue

• Similar to the whitelisting capabilities for node selectors, we need a whitelisting capability for taints and tolerations. For example, if a user can use a toleration

key: "server-license"
  operator: "Equal"
  value: "jboss"
if he has payed for JBoss we might want to prevent that he can use that value "jboss" if he has not subscribed to that service.
key: "server-license"
  operator: "Equal"
  value: "jboss"

• Similar, we would like to be able to default certain customers (with a preference) for certain nodes

key: "customer"
  operator: "Equal"
  value: "cust1"

and must prevent via a whitelist that customer1 can use a value of cust2