build out initiatives page

[jules32]

Move to replace "Champions Program" at top-level nav-bar with "Initiatives" that would provide a list that would then link out to:

• Champions Program
  • link to page & series
• Mentors Framework
  • multi-year
  • ex: link to NASA & cookbook
  • includes profess dev with Carpentries instructor training or mentor-coach with Tara Robertson
• Pathways to Open Science
  • link to page
• Reflections
  • link to booklet
• Community Calls
  • link to blogs

Other?