flexctl

[davissp14]

Adds flexctl to make interfacing with backups easier. We can also work to move the various repmgr commands here as well to make life easier.

root@8d9ee4fe0d9038:/# flexctl backup
Usage:
  flexctl backup [command]

Available Commands:
  create      Creates a new backup
  list        Lists all backups
  show        Shows details about a specific backup