Add ELIXIR LP editorial message from Issue 1200

[PhilReedData]

Summary of changes

• Include the ELIXIR learning paths editorial instructions and links to the About pages.
• Added to the en : register : learning_paths : editorial field.
• I don't know how to add to the LP>New page side bar. I have written text there but I don't know how to add links.
• I am also adding to the new TeSS Docs (separate repo).

Motivation and context

• Requested in ELIXIR Learning Paths process inclusion when registering new learning paths #1200 by the Learning Paths Focus Group.

Screenshots

Checklist

• I have read and followed the CONTRIBUTING guide.
• I confirm that I have the authority necessary to make this contribution on behalf of its copyright owner and agree
  to license it to the TeSS codebase under the
  BSD license.