Update Core Tenets

The beta testers asked that the core tenets listed here be updated. The testers gave this specific feedback:

Under "Core Tenets," I think making it clearer as to the type of compliance they are talking about should be considered. Are they talking about compliance with a particular DoD standard, a security standard, STIGs, and operational standard, etc.?

We should also include a link to the DoD Enterprise DevSecOps Fundamentals guide.