Design for AWS IaaS targeting

[joeduffy]

We need a design for how to target AWS as the cloud provider and ECS as the scheduler.

[joeduffy]

There is a start of this at AWS and ECS. There are still many open questions, however, particularly how the primitive Mu stack types project onto the target abstractions.

[joeduffy]

Most of this has evaporated, given our decision to expose elements in their raw form. I am tempted to close this out, however surely we will face some of the unanswered questions in the above-linked documents as we bring up the V0.9 and V1.0 systems. So I will keep this open for now.

Note that most of the above open issues are now part of the higher-level layers. For example, when we ever had the notion of a "cluster" or "VM" or something that is more abstract than just provisioning resources in their raw form. These used to be part of the mu namespace itself, however now these have become part of the cross-cloud mu/x package.

[joeduffy]

As described above, this is obsolete. (Or, specifically, we've changed how we are approaching this problem.) I'm closing this out in favor of #78.