Make dogtag an optional (and default un-) installed component in a replica.

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

install/tools/Makefile.am

@@ -5,6 +5,7 @@ SUBDIRS = 			\
         $(NULL)
 
 sbin_SCRIPTS =			\
+	ipa-ca-install		\
 	ipa-dns-install		\
 	ipa-server-install	\
 	ipa-replica-conncheck	\