Improve Jenkins X testing infrastructure

[ankitm123]

Testing is a bit thin for Jenkins X atm. This leads to buggy releases and creates hassles for end users.
There is a lot of work that can be done to improve the current testing landscape.
Few things I have in mind include

• Document about the infrastructure used to produce Jenkins X infrastructure
• Supply chain security
  • SBOMs (signed) - we only do this for artifacts produced in GitHub. For artifacts produced in jx GCP infrastructure
  • generate attestations
  • better integration with tekton chains
• Enabling codecov in all the jx repos (We have it enabled only for jx and jx-pipeline atm)
• Getting unit test coverage close to 80% (we are not chasing high test coverage - but we want to refactor with confidence and make it easier for new contributors to write tests for their features)
• Run tests across AWS and GCP (we will add azure in the future)
• Run compatibility tests across supported kubernetes versions (using kind) to know when new changes break compatibility with existing kubernetes versions

In addition we need to plan out tests for LTS!
jenkins-x/enhancements#44

@joker00777 and @ankitm123 will be coordinating to start the work, and form an infrastructure SIG soon!

[ankitm123]

doodle poll: https://doodle.com/meeting/participate/id/enxz3oRb