Make it easy to compare 2 versions of tests

[John_Milasch]

When we're executing manual tests, sometimes mistakes are found in the steps. So we have to reopen the test, edit, request for review and finally get the test approved.

When tests have more than 10 steps or when changes are significant enough, it is very hard to compare 2 revisions of the test.

I'd like to request a feature in X-ray that allows for comparing 2 versions of a test.