This is a full rewrite independent of the previously removed cryptpad
module, managing cryptpad's config in RFC0042 along with a shiny test.
Upstream cryptpad provides two nginx configs, with many optimizations
and complex settings; this uses the easier variant for now but
improvements (e.g. serving blocks and js files directly through nginx)
should be possible with a bit of work and care about http headers.
the /checkup page of cryptpad passes all tests except HSTS, we don't
seem to have any nginx config with HSTS enabled in nixpkgs so leave this
as is for now.
Co-authored-by: Pol Dellaiera <pol.dellaiera@protonmail.com>
Co-authored-by: Michael Smith <shmitty@protonmail.com>