Respect InstallConfig.Platform.AWS.UserTags

[wking]

This operator currently sets tectonicClusterID, but seems to ignore UserTags, which we use for things like expirationDate (openshift/release#1761). openshift/installer#465 is in flight with a generic helper that may make it easier to get the appropriate tags, but I'm not clear on how well that will plug in here. I'm also not sure how this plays with worker machine-sets possibly moving into the installer (CC @abhinavdahiya).

Thoughts?

[enxebre]

Closing this as machines definition lives on the installer now
For reference:
openshift/installer#468
https://github.com/openshift/installer/tree/master/pkg/asset/machines