Add support for junit file output

[shahzad31]

We should add support for junit file output, that will make it easy to integerate synthetics test into CI

[shahzad31]

we can use something like this perhaps
https://github.com/microsoft/playwright-test

example:
npx folio --reporter=junit,line

[vigneshshanmugam]

We dont support custom reporters at the moment other than the base and json, However it depends if we want to go via the path of being a test runner vs a synthetic tool.

[andrewvc]

I personally love the idea of a JUnit reporter, IMHO we want to do both. Write the test locally, run it in CI, then deploy it to production. CC @paulb-elastic @drewpost

[shahzad31]

can we please prioritise this, while integrating into CI, it's always a guess which format to use to get elastic/synthetics tests output .

@v1v faced the same problem.