fix(policy.tf): split controller policies to avoid exceeding the 6,144 character IAM policy size limit

Description

Split the single monolithic Karpenter controller IAM policy into 5 focused sub-policies to avoid exceeding the AWS IAM managed policy size limit of 6,144 characters. This follows the upstream fix in karpenter-provider-aws#8690.

The single KarpenterController policy is now split into:

• NodeLifecycle — EC2 instance/fleet lifecycle operations (RunInstances, CreateFleet, CreateLaunchTemplate, CreateTags, TerminateInstances, DeleteLaunchTemplate)
• IAMIntegration — IAM operations (PassRole, CreateInstanceProfile, TagInstanceProfile, AddRoleToInstanceProfile, RemoveRoleFromInstanceProfile, DeleteInstanceProfile)
• EKSIntegration — EKS operations (DescribeCluster)
• ResourceDiscovery — Read-only discovery (EC2 Describe*, SSM GetParameter, pricing:GetProducts, IAM GetInstanceProfile/ListInstanceProfiles)
• Interruption — SQS queue actions (conditional on spot termination)
• Custom iam_policy_statements are placed in a separate Additional policy when provided.

Motivation and Context

Fixes
#3637
#3512
The single KarpenterController IAM policy document exceeds the AWS IAM managed policy size limit of 6,144 characters.
This causes LimitExceeded: Cannot exceed quota for PolicySize: 6144 errors during terraform apply.

Breaking Changes

Yes — the controller IAM policy resources change from count-based indexing to for_each with string keys:

• aws_iam_policy.controller[0] → aws_iam_policy.controller["NodeLifecycle"]
• aws_iam_role_policy.controller[0] → aws_iam_role_policy.controller["NodeLifecycle"]
• aws_iam_role_policy_attachment.controller[0] → aws_iam_role_policy_attachment.controller["NodeLifecycle"]

moved blocks are included in migrations.tf to automatically migrate the existing single policy to the NodeLifecycle key. The remaining 4 sub-policies (IAMIntegration, EKSIntegration, ResourceDiscovery, Interruption) will be created as new resources.

How Has This Been Tested?

• I have updated at least one of the examples/* to demonstrate and validate my change(s)
• I have tested and validated these changes using one or more of the provided examples/* projects
• I have executed pre-commit run -a on my pull request