Avoid Tower in notifications for embedded ansible

ManageIQ should not indicate that anything "Tower" exists when dealing
with Embedded Ansible.  This should change the logs and notifications to
use a more "embedded ansibly" term when talking about embedded ansibly
things.

Before:

  "The operation Ansible Tower Credential creation (name=...) on
  Tower(manager_id=...) completed successfully."
  ^^^^^

After:

  "The operation Ansible Automation Inside Credential creation (name=...)
  on EMS(manager_id=1) completed successfully."
     ^^^

https://bugzilla.redhat.com/show_bug.cgi?id=1458593

app/models/manageiq/providers/ansible_tower/shared/automation_manager/tower_api.rb

@@ -35,7 +35,7 @@ def notify(op, manager_id, params, success)
         :options => {
           :op_name => "#{self::FRIENDLY_NAME} #{op}",
           :op_arg  => "(#{op_arg})",
-          :tower   => "Tower(manager_id=#{manager_id})"
+          :tower   => "EMS(manager_id=#{manager_id})"
         }
       )
     end