Replace many author blocks with their entities

[linkmauve]

I’ve done it manually so far, and created an entity for every recent author with more than one XEP. I’ve also gone through older XEPs and replaced the blocks with entities when appropriate.

You should obviously ignore the CI warning, I modify many XEPs at once.

This fixes parts of #741.

[guusdk]

Both CI scripts fail:

• the 'Triage' script simply can't process changes to more than one XEP - I've not addressed that
• the 'XEP validation' script can process multiple XEPs - it is (correctly) reporting validation issues that predate @linkmauve's changes. I've created a couple of new PRs that address most of these issues.