Switches SG rules to from nested to top-level resources and exports the
SG ids so that users of the module can define additional rules for their
Vault instances and/or the Vault ELB.
While this change should be backwards compatible, applying the new rules
might result in a very brief interruption of Vault service as:
(1) Old nested-resource SG rules are cleared
(2) New SG rules are applied one by one
Seth Vargo