feat(eks): output update-kubeconfig command

[eladb]

Synthesize a CloudFormation output that shows the aws eks update-kubeconfig
that needs to be executed in order to connect to the cluster. This command will
include the IAM masters role ARN if applicable.

Disable all other outputs by default, but added outputXxx options to enable.

Fixes #3664

BREAKING CHANGE: cluster name output will not be synthesized by default. instead we synthesize an output that includes the full aws eks update-kubeconfig command. You can enable synthesis of the cluster name output using the outputClusterName: true options.

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[eladb]

@pahud let me know if this addresses #3664

[mergify]

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