Cross account resource management (CARM)

[a-hilaly]

This issue is about AWS accounts management within a single Kubernetes cluster.

We want to:

• Allow users to securely create resources across multiple AWS accounts without having to own/manage multiple Kubernetes clusters.
• Help users maintain/administer controllers access to stored AWS accounts.
• Limit controllers permissions when calling AWS API.
• Prevent unauthorized users from making CRUD operations on resources on a different AWS account.

Link to CARM design proposal

Related to: #3 and #25