Import / export and E2E tests

[nofurtherinformation]

This PR adds two things: end to end testing and a nascent tool to import and export zone assignments

Description

• Adds Cypress and a baseline configuration to build further tests
• Adds a tool to import and export assignments as JSON

Reviewers

• Primary: @raphaellaude
• Secondary: @mapmeld

Checklist

• Integrate cypress
• Add basic cypress workflow to load data
• Document cypress commands
• Add export as JSON clipboard
• Add export as JSON file
• Add import from JSON text area
• Add import from JSON file
• Add CSV imports ?

Screenshots (if applicable):

[nofurtherinformation]

After reviewing priorities, this is not actually as required as I thought, closing this for now.