Use base container for Cypress testing instead of own container

[maurofmferrao]

We need to remove Dockerfile.cypress and use package.json Cypress dev dependecy in Dockerfile.ci instead.

• Remove Dockerfile.cypress
• Set specific Cypress version in package.json
• Update Dockerfile.ci to npm install dev and not prod
• Update test suite to use base container's defined cypress version for testing

[dasgarner]

Turns out we can't use the base container for this, because the base container doesn't have node in it. There are two choices therefore - we install node in the base container, or we continue to use the separate cypress container, but with a named version in the dockerfile.

I think on balance it would be better to continue using the cypress container.