Add support for CIS hardening as an option with generate_bundle.sh

[dosaboy]

original lp bug - https://bugs.launchpad.net/stsstack-bundles/+bug/1883586

Here's something that I have done to get this done for the time being. But may be useful to add to the set of scripts to do it natively via generate-bundle.sh

https://git.launchpad.net/~arif-ali/+git/bt_versioned_overlays/commit/?id=d291ab8292392a800ea469561856c006c706f2f7

I may have a look, and see if I can do a MR later. I don't think it should be too complex to add on