Refactor VM post_create_actions into separate sub-classes

Moved logic to raise created_event into sub-classes
Moved infra logic for inherit of tags and scanning based on host into Infra sub-class

https://bugzilla.redhat.com/show_bug.cgi?id=1044597
Merge pull request #1094 from gmcculloug/vm_template_created_event

Refactor VM post_create_actions into separate sub-classes