Feature: Telemetry: actual vs. estimated duration for test execution

[atodorov]

This will compare the estimated duration (from #1923) vs the actual execution duration (from #1924) to find for which TestCases the estimated and actual are different. This will answer the question: for which TCs the estimation is close to reality. Alternatively which TEs took disproportionately short/long to execute this time.

Still not sure how to represent visually, maybe a distribution chart will work good here.

Note: There is also a total duration for a TestRun which is TR.start_date - TR.stop_date and that may also include time for organizational items, infrastructure or other stuff. TE.actual_duration is the actual amount of time it took to execute a test.

[atodorov]

Related 840fa03856f71da340d8b85711a5b5c2e69d8a80 - timedelta2seconds