chore: remove static AWS credential bootstrap

[glitchedmob]

Removes the legacy static AWS credential bootstrap now that External Secrets and OpenBao use Kubernetes workload identity.

• Stops passing the credential SSM paths through Terraform-backed Ansible inventory.
• Stops reading and rendering the long-lived IAM access key into Kubernetes Secrets.
• Removes the obsolete AWS Secret templates while preserving SeaweedFS credential seeding.
• Keeps workload roles and application credentials unchanged.

[glitchedmob]

Coordination: merge this cleanup before applying sgfdevs/infra-aws-core#6 so future cluster bootstraps no longer request the legacy parameters.

[github-actions]

Terraform plan

Artifacts: https://github.com/sgfdevs/infra-vm-workloads/actions/runs/33289011579

Show summary

CHANGE	RESOURCE
update (3)	module.sgfdevs_k3s_cluster.ansible_host.workload["sgfdevs-k3s-01"]
	module.sgfdevs_k3s_cluster.ansible_host.workload["sgfdevs-k3s-02"]
	module.sgfdevs_k3s_cluster.ansible_host.workload["sgfdevs-k3s-03"]

Decrypt artifacts:
openssl enc -d -aes-256-cbc -pbkdf2 -in tfplan.enc -out tfplan -pass pass:$OUTPUT_ENCRYPTION_KEY
openssl enc -d -aes-256-cbc -pbkdf2 -in tfplan.txt.enc -out tfplan.txt -pass pass:$OUTPUT_ENCRYPTION_KEY