EKS Nodes: Change node type and count for default node group

[sablumiah]

Change node type and count for default node group to handle node memory alerts

Current:

node_groups_count = { live = "54"

node_size = { live = ["r5.xlarge", "r5.2xlarge", "r5a.xlarge"] }

New:

node_groups_count = { live = "36"

node_size = { live = ["r6a.2xlarge", "r5a.2xlarge", "r5.2xlarge"] }

Test in test cluster to see if best to do count and size separately as this change will create a new node group and move over all pods.

m6a.2xlarge may not be available unless we update the vpc cni addon to a more recent version. If not, we can use m5a.2xlarge as primary instance type.