Allow multiple policies of the same type (e.g. jwt-validation-policy) for different pointcuts

[paclife]

We have a need to specify the same policy, but configure it differently depending on the endpoint. For example we may want to apply a JWT validation policy that enforces the scope claim for a specific endpoint, and then another JWT validation policy with a different scope claim for another endpoint.

Along the same lines, it'd be great if only the policies defined in anypoint.json are reflected in API manager (i.e. remove any policies not defined in code).