Allow to exclude roles from plays with --exclude-roles command line parameter

tasks/main.yml

@@ -2,7 +2,7 @@
 # file: roles/commonauth/tasks/main.yml
 
 - include: commonauth.yml
-  when: common_execute == 'yes' and role_commonauth_completed is not defined
+  when: '"commonauth" not in excluded_roles and role_commonauth_completed is not defined'
 
 - name: 'Commonauth | Remember that this role had been run'
   set_fact: role_commonauth_completed=true