Update site to describe saf cli

[wdower]

MITRE saf cli has combined inspec_tools, heimdall_tools and a bunch of new features for SAF into a single utility; the CMS SAF site needs to reflect this.

Homepage:

• Update "How CMS SAF Does It" to reference saf cli instead of deprecated tools -- match MITRE SAF homepage
• Update tool cards to match MITRE SAF set of cards (with the extra CMS functions added on top as usual)
• Fix tool card for Heimdall Lite so that its demo link uses heimdall-lite.cms.gov instead of the mitre.org one

Normalize:

• Rename/reword section for heimdall_tools to "saf convert"
• Move it up to right underneath the first section describing what HDF is so that people will notice the converters immediately
• Make a new section for "Creating New Mappers" saying something like "want a mapper you don't see here? take a look at our wiki"

FAQ:

• Add a new FAQ to explain what happened to the old tools; see the MITRE SAF FAQ page