Update e2e testing framework, add base tests

[jeffpaul]

Is your enhancement related to a problem? Please describe.
This issue is a placeholder for adding in 10up's new e2e testing framework powered by Cypress and GitHub Actions that first started in Simple Podcasting and Restricted Site Access.

Describe the solution you'd like

• add base Cypress setup files
• add base GitHub Action
• add base test cases
• add test cases to replicate existing WP Acceptance tests
• add tests for the Facets feature

Designs

Describe alternatives you've considered

Additional context

[jeffpaul]

Noting a branch is up for this work: https://github.com/10up/ElasticPress/tree/test/2375