Allow use of both public and wildcard keys

In production we want to be able to include both the wildcard
(*..performance.service.gov.uk) and the public
(*.performance.service.gov.uk) keys and certs.

Needed to update hiera to be able to reference hiera vars in yaml
Merge pull request #489 from alphagov/public-and-env-ssl-keys

Allow use of both public and wildcard keys