Ontology: The `restricted_ports` field should be an array of strings

[lebogg]

In line 2415, the restricted_ports should be a repeated field of strings, right?

security-metrics/ontology/v1/ontology.proto

Lines 2405 to 2416 in 0fed865

	// L3Firewall is an entity class in our ontology. It can be instantiated and contains all of its properties as well of its implemented interfaces.
	message L3Firewall {
	option (resource_type_names) = "L3Firewall";
	option (resource_type_names) = "Firewall";
	option (resource_type_names) = "AccessRestriction";
	option (resource_type_names) = "Authorization";
	option (resource_type_names) = "SecurityFeature";
	bool enabled = 9476;
	bool inbound = 1000;
	string restricted_ports = 7341;
	}

I assume the metric L3FirewallRestrictedPorts would not work correctly at the moment