feat(k8s): introduce several retry functions to deal w/ flaky apis

[mhulscher]

Description

To deal with flaky kube-apiservers we wrote several retry functions. Related issue: aws/containers-roadmap#1810 (comment)

I am unsure whether these functions will be considered, but it was little effort to make a PR.

TODOs

Read the Gruntwork contribution guidelines.

• Update the docs.
• Run the relevant tests successfully, including pre-commit checks.
• Include release notes. If this PR is backward incompatible, include a migration guide.

Release Notes (draft)

Added k8s functions: RunKubectlWithRetry, RunKubectlWithRetryE, RunKubectlAndGetOutputWithRetry, RunKubectlAndGetOutputWithRetryE, KubectlApplyFromStringWithRetry, KubectlApplyFromStringWithRetryE

Migration Guide

N/A

[mhulscher]

If these additions are acceptable, I can consider writing tests. However, I am unable to run any existing test. For example I tried running this (go test -timeout 30m -run TestRunKubectlAndGetOutputReturnsOutput) in either the root of the project or the modules/k8s directory, and I am told that there are no tests to run. I am not a developer so this is entirely my fault, so I could use some pointers here :)

[denis256]

Hi,
to run Kubernetes-specific tests should be used tag kubernetes, go test --tags=kubernetes