Major Description
Now that Detectors can be found and loaded using the service pattern used by parsers, we should add a similar option to the TikaCLI to print out the available detectors
TikaCLI already has a --list-parsers option, so this should logically be --list-detectors
With parsers, we have the option to also list information on the supported mimetypes. This probably doesn't make sense for detectors, so we can go with a simpler pattern