A dogtag replica file is created as usual. When the replica is installed
dogtag is optional and not installed by default. Adding the --setup-ca
option will configure it when the replica is installed.
A new tool ipa-ca-install will configure dogtag if it wasn't configured
when the replica was initially installed.
This moves a fair bit of code out of ipa-replica-install into
installutils and cainstance to avoid duplication.
https://fedorahosted.org/freeipa/ticket/1251
