test[e2e]: refactor, and add to public-facing editor flow test

[jamdelion]

Trello ticket: https://trello.com/c/dBmTyu9F/3017-test-each-planx-component-via-an-e2e-test

In this PR

• Refactor to use page object model for editor
• Split out the create-flow test into two files to reduce length/speed up local test runs
• Add to the 'public facing' part of the 'create-flow' test and added helpers that matched the format of the existing ones

Next steps

You might have noticed I've stopped at the drawBoundary component! I think I might shift some of the 'add component' steps around so that I can tackle easier components first (there is a separate ticket for geospatial components). 😅

❓ Perhaps I can change the test to not be order-dependent - i.e. create many parallel flows that have different components in them, rather than one long one. This might be more like unit testing though, and perhaps would lose some of the benefit of trying to have a more realistic flow (with many different components in it).

[github-actions[bot]]

Removed vultr server and associated DNS entries