E2E: Make clustername in e2e test configurable and set ec2 instance id as cluster-name

[mrajashree]

Currently name of cluster created by e2e test is not configurable

• Accept it as an env var and make it configurable. So when running tests locally you can specify cluster name as env var (already done by https://github.com/aws/eks-anywhere/pull/212/files)
• For tests running in the e2e job, assign instanceID as the test name. The instanceID obtained here can be set as an env var just like the job ID

[jaxesn]

Is #212 the first part of this?

[mrajashree]

updated the issue check list to reflect that