It moves documentation from doc/ to docs/, moving support documentation under that tree, and adding in missing support documentation (such as issue/PR templates).
It versions the documentation, providing both v1 and v2 trees (v1 based off the 1.8.6 release). Existing pages now redirect to the most recent appropriate document.
It adds a migration document, detailing how to upgrade from v1 to v2.
This patch accomplishes three things:
doc/todocs/, moving support documentation under that tree, and adding in missing support documentation (such as issue/PR templates).