fix(eks-nodegroup): fix nodegroup and add more example for provisioning

[haarchri]

Signed-off-by: haarchri chhaar30@googlemail.com

Description of your changes

• add example for eks nodegroup
• fix issue for eks nodegroup with unexpected format for ID (), expected cluster-name:node-group-name:
• add example for eks nodegroup iam role/attchment

Fixes #187

I have:

• [x] Read and followed Crossplane's contribution process.
• [x] Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

NAME                                                   READY   SYNCED   EXTERNAL-NAME        AGE
cluster.eks.aws.jet.crossplane.io/sample-eks-cluster   True    True     sample-eks-cluster   39m

NAME                                                READY   SYNCED   EXTERNAL-NAME   AGE
nodegroup.eks.aws.jet.crossplane.io/sample-eks-ng   True   True     sample-eks-ng   28m

NAME                                                READY   SYNCED   EXTERNAL-NAME        AGE
role.iam.aws.jet.crossplane.io/sample-eks-cluster   True    True     sample-eks-cluster   7h34m
role.iam.aws.jet.crossplane.io/sample-node-role     True    True     sample-node-role     31m

NAME                                                                            READY   SYNCED   EXTERNAL-NAME                                   AGE
rolepolicyattachment.iam.aws.jet.crossplane.io/sample-cluster-policy            True    True     sample-eks-cluster-20220508185853757700000001   41m
rolepolicyattachment.iam.aws.jet.crossplane.io/sample-node-group-cni-policy     True    True     sample-node-role-20220508193956943000000001     31m
rolepolicyattachment.iam.aws.jet.crossplane.io/sample-node-group-ecr-policy     True    True     sample-node-role-20220508190934091000000001     31m
rolepolicyattachment.iam.aws.jet.crossplane.io/sample-node-group-eks-policy     True    True     sample-node-role-20220508190918097700000001     31m
rolepolicyattachment.iam.aws.jet.crossplane.io/sample-vpc-resource-controller   True    True     sample-eks-cluster-20220508194005305700000001   40m