README information for "modernized" templates (4 templates going to OpenC2, August 2021)

List of changes since prevous templates:
- Several sections relocated:
-- References and main Notices block are now Appendices.
-- Removed previous "IPR Policy" section (that material is only in "Status" now)

- inserted additional comment lines into Markdown template
-- fully-defined expected front-page URIs, to simplify initial publication
-- additional comments to clarify which templated document sections are required or optional

- Linked to new OASIS logo.

- cover page - inserted white space after date (   within Markdown generates blank paragraph in HTML )


*** CSS files online ***

OASIS staff have installed two fairly simple .css files developed for use with Markdown-styled documents into the OASIS Library.
They are permanently web-accessible and are now available for use as needed.

-- Both current files can be linked directly from your HTML documents if needed.
-- We are also including both .css files in the /styles subdirectory included with this template ZIP package.

File names:
- The current baseline .css file is https://docs.oasis-open.org/templates/css/markdown-styles-v1.7.3.css.

- An upgraded .css file (with contributions from Dave Kemp for OpenC2 TC) is also available, at:
-- https://docs.oasis-open.org/templates/css/markdown-styles-v1.7.3a.css

Change/upgrade description for "markdown-styles-v1.7.3a.css":
- "/* dk 2020-10-21 - v1.7.3a (unofficial for jadn, based on 1.7.3) update block quotes and code blocks */"
Expanded description:
- slightly lighter gray background for text blocks
- code blocks are not formatted with ragged right borders
- block quotes have wider left margin, and have a visible left-side border

Both files are intended to remain permanently available at:
- https://docs.oasis-open.org/templates/css/markdown-styles-v1.7.3.css
- https://docs.oasis-open.org/templates/css/markdown-styles-v1.7.3a.css