Cluster auditor: contributing guide addition, helm test change

Package Merge Request

Package Changes

Add contributing doc for cluster auditor

Remove overrides for helm test in BB CI values - effectively this allows the test to pass even if there is no data present in the dashboard. After a number of back and forth changes and attempts this appears to be the best path forward:

• Too many retries will time out the helm test (it already runs 5 times)
• Consistently inconsistent behavior with data showing up or not, definitely seems to be timing with data populating in the dashboard
• Test will continue to check both the prometheus target and the dashboards existence
• Cluster auditor will be going away/changing in BB 2.0 so I think this modification is acceptable for the short term in between period

Package MR

https://repo1.dso.mil/platform-one/big-bang/apps/core/cluster-auditor/-/merge_requests/89