Feature request: Add support for mixed instances policy

[michellebeard]

Use case

Add support to analyze EKS clusters that use a MixedInstancePolicy.

eksup analyze --cluster foo --region us-west-2 
Error: Launch template not found, launch configuration is not supported

Note: The error message provided about is misleading or limiting. The cluster being scanned does not use launch configurations.

Solution/User Experience

Enable eksup to autodetect a mixed instance policy.

Alternative solutions

Add support to disable ASG checks.

[bryantbiggs]

hmmm, yes we could probably just log out something like "Not found - skipping check xxx" to let it keep analyzing