Add support for lists

[danotorrey]

Add support for Logpush list values (FirewallMatchesRuleIDs, FirewallMatchesSources, FirewallMatchesActions).

graylog-s3-lambda/src/main/java/org/graylog/integrations/s3/codec/CloudFlareLogpushCodec.java

Lines 114 to 125 in fe745e7

	// TODO: The Initial version can be shipped without support for lists.
	// Arrays can be comma-separated. See these examples:
	// "FirewallMatchesActions": [
	// "allow"
	// ],
	//"FirewallMatchesSources": [
	// "firewallRules"
	// ],
	//"FirewallMatchesRuleIDs": [
	// "test"
	// ],
	// message.addAdditionalField(key, valueNode.toString());

I do not plan to support this in the first version. This should be an easy add in a future version.