Extract Options helper class from CLI class

The CLI class was becoming very unwieldy and hard to reason about.
Extract the command line options parsing functionality into a helper
class and change the signature of `CLI#run` to return the exit code
rather than have the method raise a `SystemExit` error itself.

Additional changes to come will extract more functionality from this
class to simplify it further.

Change-Id: I8432231ad6152313b085ef8de13bebbd22243918
Reviewed-on: http://gerrit.causes.com/44889
Tested-by: jenkins <jenkins@brigade.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>