Automatic merge from submit-queue

Coreos kube-up now with less cloud init

This update includes significant refactoring. It moves almost all of the
logic into bash scripts, modeled after the `gci` cluster scripts.

The reason to do this is:
1. Avoid duplicating the saltbase manifests by reusing gci's parsing logic (easier maintenance)
2. Take an incremental step towards sharing more code between gci/trusty/coreos, again for better maintenance
3. Pave the way for making future changes (e.g. improved rkt support, kubelet support) easier to share

The primary differences from the gci scripts are the following:
1. Use of the `/opt/kubernetes` directory over `/home/kubernetes`
2. Support for rkt as a runtime
3. No use of logrotate
4. No use of `/etc/default/`
5. No logic related to noexec mounts or gci-specific firewall-stuff

It will make sense to move 2 over to gci, as well as perhaps a few other small improvements. That will be a separate PR for ease of review.

Ref #29720, this is a part of that because it removes a copy of them.

Fixes #24165

cc @yifan-gu 

Since this logic largely duplicates logic from the gci folder, it would be nice if someone closely familiar with that gave an OK or made sure I didn't fall into any gotchas related to that, so cc @andyzheng0831