Define updated model document and templates for OASIS specifications

[paul-knight]

(Initially tracked in JIRA - https://issues.oasis-open.org/browse/TCADMIN-3836. Some links to logos, and info on the colors is there.)

This work has two major parts:

• Define model OASIS specification in HTML for approval.
• After approval, upgrade templates and processes so that the HTML output (at least) will follow the approved model.

This will affect multiple templates in DOCX, ODT, Markdown, and likely other formats, and will require coordination with TCs using DocBook, DITA, ReSpec, XML, and other document preparation systems.

This will also affect the "Notes" model document and templates.

[paul-knight]

Also, as a model of one approach (title/headings using the logo color cobalt Hex #2248E5, with hyperlinks in a light purple), see OpenDocument CS02 when published in a day or two:

• https://docs.oasis-open.org/office/OpenDocument/v1.3/cs02/part1-introduction/OpenDocument-v1.3-cs02-part1-introduction.html