SD Enhancement: Created a variable for the ROSA classic product

Author: EricPonvelle

_attributes/attributes-openshift-dedicated.adoc

@@ -50,4 +50,6 @@
 :hcp: hosted control planes
 :hcp-title: ROSA with HCP
 :hcp-title-first: {product-title} (ROSA) with {hcp} (HCP)
+:rosa-classic: ROSA (classic architecture)
+:rosa-classic-first: {product-title} (ROSA) (classic architecture)
 //ROSA CLI variables