Collective Wisdom learn page

[rufuspollock]

relocate https://lifeitself.org/collective-wisdom to https://lifeitself.org/learn/collective-wisdom

Part of #568

Migrate that content to a subpart of that page.

Add other links e.g.

• [ ] https://lifeitself.org/blog/2020/10/24/collective-wisdom-reflections
• [ ] https://lifeitself.org/blog/2020/06/22/bridging-the-wisdom-gap
• [ ] blind-spots ...