🌱 chore: configure janitor to cleanup aws resources

[salasberryfin]

What this PR does / why we need it:

Enable aws-janitor to clean resources using a mark and delete approach (first execution mark/next delete), including:

• EKS clusters.
• Auto Scaling Groups.
• Load Balancers.
• Security Groups.
• CloudFormation stacks.

Resources that include the tag janitor-ignore will be skipped.

Which issue(s) this PR fixes:
Fixes #368

Special notes for your reviewer:

This PR is waiting on an initial release of https://github.com/rancher-sandbox/aws-janitor, which will be created after rancher/aws-janitor#4.

aws-janitor runs after azure-janitor. It will run even if the previous job fails and it'll be skipped only if the action is cancelled.

Checklist:

• squashed commits into logical changes
• includes documentation
• adds unit tests
• adds or updates e2e tests