Replace ReSpec HTML drafts with Markdown versions

[zimeon]

Fixes #554

There is the following fixup required:

• in spec, rendered version: https://zimeon.github.io/ocfl-spec/draft/spec/
  • Indentation in example in 3.5.3.1 Version is not right: empty.txt and empty2.txt should be at some level
  • Non-normative notes that span multiple paragraphs need a tweak to avoid the quote bar having breaks in it
  • Adjust wrapping in RFC2119 reference so that the markdown doesn't incorrectly pick it up 1997. as the start of a numbered list.
• in implementation notes, rendered version: https://zimeon.github.io/ocfl-spec/draft/implementation-notes/
  • In section 2.2, move examples to after the descriptions of Flat, PairTree and Truncated

If we have approval to go ahead (and commitment not to merge anything else in the meantime) that I can do these and get re-approval before merge. Must be careful to do a squash&merge

[awoods]

Should we also remove: draft/respec-w3c-common.js?

[awoods]

I am happy to move the current PR (which is fantastic) forward and then iterate on the refinements. Potential such refinements, in addition to those noted in the PR description:

1. The additional title at the top of the document seems unnecessary
2. Is there a way of having the 'table of contents' be in a side panel, so that it is always available.

Thanks!

[zimeon]

Should we also remove: draft/respec-w3c-common.js?

Yes, done in https://github.com/OCFL/spec/pull/596/commits/bc8b159cae0581637b0d9d7cf70128b1e552f077

I am happy to move the current PR (which is fantastic) forward and then iterate on the refinements. Potential such refinements, in addition to those noted in the PR description:

1. The additional title at the top of the document seems unnecessary

We use this "extra" title (actually the site.title) on the homepage and news page. I have added into _layouts/default.html a check for an extra page variable page.no_site_title which can be used in the front matter to disable the extra title, this is added as no_site_title: true in both spec and implementation notes.

2. Is there a way of having the 'table of contents' be in a side panel, so that it is always available.

Yes, may take some work to get it right but this is the case for IIIF specs. See, e.g. https://iiif.io/api/presentation/3.0/ --> https://github.com/OCFL/spec/issues/597

[zimeon]

Have addressed manual fixup issues noted in https://github.com/OCFL/spec/pull/596#issue-1243451691

Rendered versions for review:

• https://zimeon.github.io/ocfl-spec/draft/spec/
• https://zimeon.github.io/ocfl-spec/draft/implementation-notes/