(Avital) Task scope: Document the security features we support - FIPS, fapolicyd, and SELinux.

This is a new section for both Sat Server install guides.

Note: This is conceptual information, not procedures.

We could create a short concept module called "Security considerations features"  in the "Preparing for installation" section of the Installation guide. Eventually, it would be moved to the "Planning" section, which has not yet been created.

Update Let's move this section to the Deployment considerations section of the Planning guide.