find a solution for re-using md files

[crisaless]

it would be great to be able to re-use existing docs md files in more than one part of the master site. This can be done with jekyll but sphinx is not so obvious.

also considering a jekyll/sphinx hybrid site

[crisaless]

just tested and confirmed we can include files from other parts of the repo using symlinks.

For example - to re-use a file from the Chaise user docs into the top-level user's guide - run this from docs-src/users-guide/

ln -s ../chaise/user-docs/contexts.md annotations-context.md

The contents from the chaise file would be displayed in a new file: /users-guide/annotations-context.html and github recognizes the symlink.