Capacity plans should return recommended autoscaling policies

[jolynch]

Right now we just make a recommendation like "12 m5d.2xlarge" but for software that can autoscale (stateless java apps, elasticsearch etc ...) it would be nice if we could return a hint of the autoscaling policy.

Step 1: Define how we will represent a scaling policy (e.g. how to represent various metrics like CPU utilization etc ...)
Step 2: Make the models return them

[jolynch]

I think we can just return an interval for the count and just do something simple like 4x in either direction with reasonable clamps (min 2, max based on cost (nothing more than 100k))