The debug command enables and disables various settings intended to 
describe the cli's own behavior.   In addition, some of the choices
allow nested invocation of various other tools, intended to debug
various related controller components, for example, 'debug cassandra-cli'
is intended to enter the cassandra cli to view internal database state,
and 'debug bash' is intended to enter a bash subshell to gain access to
the internal environment of the controller.