Updates to AMI creation utility and autoscaling lambda (#42)

* Update lambda autoscaler to remove windows hourly-billing workarounds, add jenkins new name for master node, change launch parameters to use default launch template version instead of using environment variables to specify, update descriptions of worker nodes.

* Add aarch64 userdata for building graviton jenkins workers.

* Update templates to perform apt upgrade on boot-up, before running jenkins worker script to prevent auto-updates from killing running CI pipelines.

* Update windows installer script to install the correct VC runtime for compiling MXnet.

* Update create AMI util with the ability to update launch templates (and set default version,) if passed.