Canal runs more pods and upgrades need a bit of extra
room to load new pods in and get the old ones out.

Default backend is now etcd3 (was etcd2).
The migration process consists of the following steps:
* check if migration is necessary
* stop etcd on first etcd server
* run migration script
* start etcd on first etcd server
* stop kube-apiserver until configuration is updated
* update kube-apiserver
* purge old etcdv2 data

Migrate older inline= syntax to pure yml syntax for module args as to be consistant with most of the rest of the tasks
Cleanup some spacing in various files
Rename some files named yaml to yml for consistancy

Includes hooks for triggering calico, kubelet, and kube-apiserver restarts
if etcd certs changed.

Add tags to allow more granular tasks filtering.
Add generator script for MD formatted tags found.
Add docs for tags how-to.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

Also fixes kube-apiserver upgrade that was erroneously
deleted in a previous commit.

kubelet via docker
kube-apiserver as a static pod

Fixed etcd service start to be more tolerant of slow start.

Workaround for kube_version to stay in download role, but not
download an files by creating a new "nothing" download entry.