Migrate primers into normal structure

[rufuspollock]

Currently have a bunch of old stuff in the primers folder

Primer stuff could just become notes e.g. in /abc/.

Acceptance

• /primers/ folder no longer exists and all content migrated into other parts of the repo

Tasks

• Assess primers folder for what we want to manage / migrate (e.g. i think the main primer pdf ArtEarthTechPrimers.pdf can go away etc)
  • Also good to check what we actually posted on the blog (e.g. i think we posted mindfulness and non-attachment ??)
• Migrate relevant stuff to /abc/ etc

[rufuspollock]

DUPLICATE of #173