testsys: `aws-k8s` migration testing with `cargo make test`
Issue number: #2149
Description of changes:
Introduces migrations to cargo make test. The added documentation in TESTING.md will help any user set up the necessary infrastructure to run migration testing with all aws-k8s variants.
Testing done:
Used cargo make -e TESTSYS_TEST=migration test to run a migration test on aws-k8s-1.21 and all tests passed successfully.
Terms of contribution:
By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.
^ addressed @jpculp comments
^ addresses @arnaldo2792 comments
^^ Address @etungsten comments ^ rebase to develop
^ spell check on markdown and automatically determine correct AMI ID using previous bottlerocket release tag.