Bump vue to 2.7 and ts to 4.7

[JackWilb]

Does this PR close any open issues?

No

Give a longer description of what this PR addresses and why it's needed

This PR raises the version of vue and typescript to get us on to the most modern versions, 2.7 and 4.7. This will make out migration to vue 3 much easier once it its available. The code is also simplified here using script setup. Now, there's no need to return the variables for the template to use at the end of the script block, all variables are just available to the template.

Provide pictures/videos of the behavior before and after these changes (optional)

N/A

Are there any additional TODOs before this PR is ready to go?

TODOs:

• [x] Test that nothing has broken

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