Enable Ruby 2.7 to install Hammer for orcharhino

Installing Hammer CLI on an EL 8 hosts that is not orcharhino Server or
orcharhino Proxy Server requires the "ruby:2.7" DNF module to be enabled.

guides/doc-Hammer_CLI/master.adoc

@@ -17,7 +17,16 @@ include::common/modules/con_hammer-compared-to-project-api.adoc[leveloffset=+2]
 
 include::common/modules/proc_getting-help.adoc[leveloffset=+2]
 
+ifdef::orcharhino[]
+// works for orcharhino with Foreman 3.11 on EL8
+:parent-dnf-module-utils: {dnf-module-utils}
+:dnf-module-utils: ruby:2.7
+endif::[]
 include::common/modules/proc_installing-standalone-hammer.adoc[leveloffset=+1]
+ifdef::orcharhino[]
+:dnf-module-utils: {parent-dnf-module-utils}
+:!parent-dnf-module-utils:
+endif::[]
 
 include::common/modules/con_hammer-authentication.adoc[leveloffset=+1]