Add amazon-cloudwatch-observability chart

[abavage]

Adding the amazon-cloudwatch-observability helm chart..
Caters for teams who heavily rely on CW in their environment.

Changes over and above the standard chart

• include eks.amazonaws.com/role-arn annotation on the serviceAccount
• Add ServerSideApply=true to crds/cloudwatch.aws.amazon.com_amazoncloudwatchagents.yaml so argo can apply it without error due to the size of the object
• Pass in the variables roleArn, clusterName, region as empty strings to be added via infrastruture.yaml (argo multisource app)