Support for setting MarketType/InstanceMarketOptions for use with "capacity-block"

[dims]

Needed for enabling/using Capacity Blocks for ML

• https://docs.aws.amazon.com/eks/latest/userguide/capacity-blocks.html
• https://docs.aws.amazon.com/eks/latest/userguide/capacity-blocks-mng.html
• https://docs.aws.amazon.com/autoscaling/ec2/userguide/launch-template-capacity-blocks.html

Ensures that LaunchTemplateData will end up with InstanceMarketOptions/MarketType when CapacityReservation/CapacityReservationID is set like so:

managedNodeGroups:
  - name: cbr
    instanceType: p5en.48xlarge
    minSize: 2
    maxSize: 2
    availabilityZones: ["us-east-2c"]  # Match AZ where reservation is deployed
    capacityReservation:
      capacityReservationTarget:
        capacityReservationId: "cr-028e8bdd6334b8012"  # Replace with your ML Capacity Block ID
    instanceMarketOptions:
      marketType: capacity-block

Notes:

• instanceMarketOptions can only be specified when there is a capacityReservation section
• "capacity-block" is the only accepted value for marketType
• capacityReservationId is passed through and is not validated, so watch your cloud formation stack to see any potential issues.

Resolves #8155

[bryantbiggs]

thank you!