Add documentation and consolidate e2e tests that test for features with Kubernetes upgrades

As mentioned here: https://github.com/aws/eks-anywhere/pull/1369#pullrequestreview-900607034

We need to list our some guidelines on when to add an e2e test to avoid adding tests that might be redundant and affect our resource limits. In order to address some of the tests with Kubernetes upgrades, we can introduce a test that includes "advanced features" for the cluster and test Kubernetes upgrade with that in one go, instead of having a separate test for each.

Begin with the discussion linked from PR #1369 and review the existing end-to-end Kubernetes-upgrade tests. Done means documenting guidelines for non-redundant feature coverage and consolidating the relevant upgrade checks into an advanced-features test while respecting resource limits.

Written by the indexing model from the issue text.