Add cli for checking CI test flakiness

[mtodor]

This PR is introducing a new cli tool for evaluating if tests are known as flaky tests or not.

How it works

1. we are collecting successes and failures in our DB
2. there is a scheduled BigQuery query that populates a table with the failure rate for the last 30 executions
3. flakechecker uses that information to compare with predefined thresholds in a configuration file

Flakechecker will handle information in the following way:

• it checks all found failed jobs (logic taken from junit2jira)

• for every failed test, it will check if it is defined as a flaky test in provided config

• if a test is not found in known flaky tests configuration -> it will fail

• if a test is found, but it didn't have 30 executions -> it will fail

• if a test is found, but the defined threshold found in DB is above the definition in configuration -> it will fail

• only if a test is found and the failure ratio in DB is below the defined threshold in config -> it will be reported as success to the CI pipeline - for that, we also need: chore(CI): Add config and call for flakechecker stackrox#13081

[janisz]

I think it will be good to split repackaging from the flakechecker into 2 PRs.

[porridge]

I started reviewing but I'm still struggling to understand the overall intent. Can you please point me at the periodic job, and maybe schedule half an hour to talk about the overall design / idea?

[porridge]

Looks good overall, but I have a whole bunch of nitpicks.

[porridge]

Also, it would be good to have documentation for this somewhere. Nothing fancy, basically what is in the PR description (after bringing it up to date) plus maybe a couple of sentences on the rationale.