Mark ZEP 1 as accepted.

[jstriebel]

• Remove sphinxmark extension.
• Add custom draft mark mechanism to ZEP 2 pages.
• Update status of specs and consolidate headers.

Built upon #258.

[jstriebel]

Deleting this in favor of #260. This is the same content, just created the MR within this repo, to have automatic CI builds for the preview.