This new pages accomplishes several interrelated things:
* Documents that Zulip Cloud runs master and how that works.
* Documents policies on how long client apps are expected to support
old releases in our compatibility matrix.
* Removes the 3-years-stale roadmap article.
* Provides a central place to talk about different versions in Zulip.
* Provides a better place to link to from our "you need to upgrade" nag.
This content is not intended to be final, but should be finalized in
the next week or so.
Fixes#18322.
This commit helps reduce clutter on the navigation sidebar.
Creates new directories and moves relevant files into them.
Modifies index.rst, symlinks, and image paths accordingly.
This commit also enables expandable/collapsible navigation items,
renames files in docs/development and docs/production,
modifies /tools/test-documentation so that it overrides a theme setting,
Also updates links to other docs, file paths in the codebase that point
to developer documents, and files that should be excluded from lint tests.
Note that this commit does not update direct links to
zulip.readthedocs.io in the codebase; those will be resolved in an
upcoming follow-up commit (it'll be easier to verify all the links
once this is merged and ReadTheDocs is updated).
Fixes#5265.
Tim Abbott
Tim Abbott
David Rosa Tamsen