[PATCH 055/153] Get ready for more mesos/aurora stage commands
[PATCH 055/153] Get ready for more mesos/aurora stage commands

- Adds a CLI AuroraStageCLI class that handle stage verbs
- 'mesos stage key file' becomes 'mesos stage create key file'
- 'mesos release key' -> 'mesos stage release key'

RB_ID=166044

(sapling split of b592806ab5de370de62bb945c3a0e1ae6c54ec8c)

pombredanne/commons,pombredanne/commons,nkhuyu/commons,jsirois/commons,ericzundel/commons,nkhuyu/commons,nkhuyu/commons,VaybhavSharma/commons,atollena/commons,WCCCEDU/twitter-commons,VaybhavSharma/commons,jsirois/commons,nkhuyu/commons,cevaris/commons,cevaris/commons,brutkin/commons,ericzundel/commons,VaybhavSharma/commons,atollena/commons,ericzundel/commons,WCCCEDU/twitter-commons,Yasumoto/commons,brutkin/commons,abel-von/commons,jsirois/commons,Yasumoto/commons,Yasumoto/commons,atollena/commons,atollena/commons,Yasumoto/commons,brutkin/commons,abel-von/commons,jsirois/commons,cevaris/commons,WCCCEDU/twitter-commons,cevaris/commons,abel-von/commons,abel-von/commons,abel-von/commons,WCCCEDU/twitter-commons,Yasumoto/commons,ericzundel/commons,cevaris/commons,nkhuyu/commons,ericzundel/commons,brutkin/commons,brutkin/commons,VaybhavSharma/commons,VaybhavSharma/commons,atollena/commons,jsirois/commons,pombredanne/commons,pombredanne/commons,pombredanne/commons,WCCCEDU/twitter-commons