Replace the external state_machine with an internal implementation

https://bugzilla.redhat.com/show_bug.cgi?id=1089061

This work refactored Job and its subclasses to use an internal implementation of state machine, removed the dependency of the state_machine gem.
these seem pretty common.
Is there a way to predefine these?
Or would that be too magical?

comments? @Fryguy / @jrafanie