feat: add toggle to optionally format Calculate output for automations

[jessicamcinchak]

Solves what we're discussing in this thread: https://opensystemslab.slack.com/archives/C5Q59R3HB/p1700494465669089

Key changes:

• Conditionally change the output data format depending on use for automations
• Simplify file structure - eg Public.tsx instead of Public/index.tsx
• Add tests

How this works:
By default, calculate writes a single value to the breadcrumbs - eg "data": { "abPath": 2 }. This is necessary to use multiple Calculate components in a row and be able to pass in number inputs (as best as I understand!).

This PR introduces an Editor-facing toggle to format the output as an array with a single string item which can then be successfully referenced to auto-answer Questions or Checklists - eg "data": { "abPath": ["2"] }.

SetValue similarly always returns an array of a single string item which is how it's able to power automations. The Pay component can successfully read a value in either format.

Test flow:
https://2468.planx.pizza/testing/a-b-testing

[github-actions]

Removed vultr server and associated DNS entries

[jessicamcinchak]

Update Calculate component output to support A/B testing automations

[jessicamcinchak]

Having a logic.test.ts isn't really an existing pattern in @planx/components/, but I think this feels like a more meaningful organisation than adding more noise to the preview store tests?

[Mike-Heneghan]

This looks great 🥳

As this develops and gets more complex I'm wondering how this could be handled to differentiate between different multivariate tests and maybe even more complex stuff like nested tests.

I think it's great this has the flexibility of what the passport variable is assigned so it could maybe be managed in a similar way to current passport variables.

I'm really excited to see how this gets used and what we can learn 👀