Update/saplings devops

[paulsheldrake]

Ticket: https://kanopi.teamwork.com/app/tasks/29421361

Updates the default circleci and docksal setup to assume we're using the saplings_child theme.

• Updates node version and cypress version for cypress tests.
• Remove storybook steps from circleci
• Updates compile theme step to use a PHP image that installs the version of node we need so we can do a composer install to get the theme dependencies at the PHP level as well.
• Updates PHP version to match pantheon.yml in pantheon deploy step

Working compile -> deployment: https://app.circleci.com/pipelines/github/kanopi/saplings-devops/12/workflows/a6da8aaf-6e19-4998-8e95-4b514736e767

Notes:

• saplings_child theme doesn't work with aggregation turned on. fixing this is out of scope of this ticket
• the cypress tests run but currently fail. fixing this is out of scope of this ticket