Improve Packer options #212
Description
To speed up launching new schedulers/workers it is possible to cache your environment and Docker image on a cloud specific VM image with Packer.
Currently this involves using VMCluster.get_cloud_init to generate the cloud init and then writing a bespoke Packer config for your chosen cloud.
It would be nice if we could go the next step and generate a Packer config for you with a similar method.