491 formal spec reorg

[kriswest]

resolves #491
resolves #482
resolves #483
resolves #629

Re-organize documentation nav, and restructures main overview/spec articles to improve readability, without changing the content of the standard.

New PR with preview
Original PR was approved by @greyseer256 and @robmoffat

• [WIP] 491 formal spec reorg #679
  The goal of this work was to raise the quality of the standard's documentation to that of a formal standard, make it more readable/navigable and to bring the governance details up to date and into the microsite.

To that end we have:

• Refactored the site navigation,
  • introduced a clearly defined formal specification section
  • incorporated the reference materials (that do most of the definition) into the standard (these were only weakly referenced before)
  • Integrated the overview pages into the main specification pages (which are now called overview)
• Improved the structure of articles
  • Deduplicated content between old overview, spec and reference articles
  • Refactored the new spec documents to improve structure (e.g. separating use-case definitions from implementation details in the API article, integrating use-case and discovery pages into appD overview)
  • Reviewed in-page navigation
• Introduced abstract pages for standard versions
  • including dates on adoption/release/obsoletion
  • acts as a landing page for 'the standard'
• Added a roadmap page to track progress on next standard version
• Created an implementations page
  • not added to nav yet, need to collect details from vendors to populate,
  • determine policy for compliance tagging

Outstanding work (to be completed during 2.0 release):

• Collect up compliance details across standard and summarize on compliance page

[nkolba]

@kriswest LGTM

What are thoughts on adding an "open source" tab in the implementations section?

[kriswest]

What are thoughts on adding an "open source" tab in the implementations section?

We're continuing the development of the implementations page on PR #714, where @robmoffat has had a go at adding badges (to help expose compliance info, when a testing process is available). As Open-source cuts across/could apply to all the types, would a badge work?

[mattjamieson]

LGTM! Minor stylistic/consistency suggestions only.

[RexJaeschke]

Well done Kris! I looked at the new organization and the higher-level section content. I reviewed the Issues labelled "formal specification" that I raised, and they appear to have been addressed.

[kriswest]

Many thanks @RexJaeschke @greyseer256 @robmoffat @mattjamieson @nkolba for your reviews across this PR and its predecessor, excited to hit the merge button on this one.