Add a sidecar example

[ChunyiLyu]

This closes #

Note to reviewers: remember to look at the commits in this PR and consider if they can be squashed

Summary Of Changes

Add a sidecar example with test. Suggestion from @yaronp68 😸

Additional Context

Github action has been very flaky these day. Create a github issue to handle that: #767

Local Testing

Please ensure you run the unit, integration and system tests before approving the PR.

To run the unit and integration tests:

$ make unit-tests integration-tests

You will need to target a k8s cluster and have the operator deployed for running the system tests.

For example, for a Kubernetes context named dev-bunny:

$ kubectx dev-bunny
$ make destroy deploy-dev
# wait for operator to be deployed
$ make system-tests

[mkuratczyk]

Nice!