Fixes #12203 - Add the Monad Manifesto

[sdwheeler]

PR Summary

Add the Monad Manifesto

• Fixes AB#448530
• Fixes Publish the Monad Manifesto #12203

PR Checklist

• Descriptive Title: This PR's title is a synopsis of the changes it proposes.
• Summary: This PR's summary describes the scope and intent of the change.
• Contributor's Guide: I have read the contributor's guide.
• Style: This PR adheres to the style guide.

[mikefrobbins]

See my comments

[learn-build-service-prod]

Learn Build status updates of commit e3a9175:

✅ Validation status: passed

File	Status	Preview URL	Details
assets/MonadManifesto.pdf	✅Succeeded
reference/docs-conceptual/developer/monad-manifesto.md	✅Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/overview.md	✅Succeeded	View (>=powershell-5.1)
reference/docs-conceptual/toc.yml	✅Succeeded	View (>=powershell-5.1)

For more details, please refer to the build report.