Asciidoc conversion of hardening guide changes

Correction

Asciidoc conversion of new and revised content for hardening guide v4.

https://issues.redhat.com/browse/AAP-48749

Author: ianf77

downstream/modules/aap-hardening/ref-sensitive-variables-install-inventory.adoc

@@ -5,8 +5,6 @@
 
 = Securing sensitive variables with ansible vault
 
-[role="_abstract"]
-
 The installation inventory file for {PlatformNameShort} contains a number of sensitive variables, such as default administrative and database passwords. 
 By default, these are stored in plain text. 
 To enhance security and comply with organizational policies, encrypt these variables using an Ansible vault file.