Add history to the dbg cli helper
Add history to the dbg cli helper

As long as we are adding readline, history persistence is also really
handy.

jjohnson42/confluent,jjohnson42/confluent,jjohnson42/confluent,whowutwut/confluent,xcat2/confluent,xcat2/confluent,jjohnson42/confluent,xcat2/confluent,xcat2/confluent,whowutwut/confluent,whowutwut/confluent,whowutwut/confluent,jjohnson42/confluent,xcat2/confluent