Investigate moving E2E test outputs to Allure

[matthewelwell]

Since our E2E test reporting is failing due to a deprecation in the Slack API (see here), we should evaluate other options for test reporting, e.g. Allure.

We can look into this (slightly stale) project or look into converting the output into a format that Allure natively integrates with (e.g. XUnit).

We should not consider moving away from TestCafe as part of this work.

[Zaimwa9]

https://testcafe.io/documentation/402825/guides/intermediate-guides/reporters