This patch does two primary things:

1) It formulates a real CN for the CA rather than assigning it the
   same name as the organiazation.  E.g. "ca.example.com" rather than
   "example.com"

2) It adds the ability to override the default ("ca.{{ .Domain }}") using
   the template system.

Fixes FAB-3455

Change-Id: I5c8085e338b5d11e236d517e275a817eb89760a5
Signed-off-by: Greg Haskins <gregory.haskins@gmail.com>