Add a "Defend Your Application" page

[maxrake]

Overview

Add a new content overview page for the "Defend Your Application" topic/concept. It will be less of a guide and meant more as a landing page to drive folks to the appropriate CI/CD integration.

Additional context

Provide more detail around the new content:

• The page will be like the current Integrations Overview page
  • It might also simply re-use that existing page
  • The content will be action oriented, with more detail and distinction made about the context (CI platforms) within which those integrations exist
  • Provide a compelling user story to help sell the value offered by the integrations
• Simple links are okay for now
  • Icons/graphics would be nice
  • Move to the "self-identify" (e.g., tile based decision tree) model later
• Get more guidance from @furi0us333 and/or the marketing team