This fixes exceptions when sending PMs in development (where we were
trying to connect to the localhost push bouncer, which we weren't
authorized for, but even if we were, it wouldn't work, since there's
no APNS/GCM certs).
At the same time, we also set and order of operations that ensures one
has the opportunity to adjust the server URL before submitting
anything to us.
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.