Support Docker runtime Lambdas

Summary

Support for Docker runtimes in lambda, currently can't install Lambda monitoring if you have "PackageType": "Image" in your Lambda.

I did not find much information regarding to this, neither warnings I spent all day trying to figure this out and found a couple of posts of people asking this issue. At least it would be nice to add a warning sepcifying that this setup is not compatible with docker images in lambda either in this repo, new relic console, blogs, etc...

Possible Solution

Perhaps instructions installing it inside the docker image that runs in lambda, you could keep the setup in the cli for linking aws accounts, setting roles with required policies, etc.