Ensure detections show up in the ES app

[linuxdaemon]

This ensures that detections show up as content in the Enterprise Security UI in Splunk

[pyth0n1c]

@linuxdaemon , great catch! Instead of hardcoding this, do you the "app" field should be specifiable in the contentctl.yml file (or similarly on the command line) with a default of SplunkEnterpriseSecuritySuite ?
I anticipate there will be users of contentctl who do not have Enterprise Security and might want to create them in a different app (although I think this will be a less common use case). Any thoughts?

[linuxdaemon]

Yeah that makes sense to me, I'll add that to my todo

[josehelps]

Lets build the config changes into another PR, for now this is perfect