Use Cypress parallelization

We've been strutting the CircleCI open source plan context deadline of 1 hour for some time now. Sometimes if the VPS is slow, we'll exceed it, causing the tests to fail and artifacts to not be saved. This is particularly annoying when tests timeout and fail, as we lose the artifacts to easily debug them.

The Cypress tests take around 40 minutes currently. The other big chunk is building biotestmine, but even if we improve that, adding more tests can easily result in Cypress alone exceeding the 1 hour limit. Therefore parallising the Cypress tests is the only approach which would work in the long-term.

I believe this feature is only available through the Cypress dashboard #709

Start by reviewing the Cypress test setup and CircleCI configuration, then investigate the Cypress Dashboard parallelization feature referenced in the issue. Done means the Cypress suite runs in parallel reliably within the one-hour context limit and test artifacts remain available when tests time out or fail.

Written by the indexing model from the issue text.