From previous tasks, the patch app should now have the relationship between advisories and templates.  When calculating the installability of an advisory for a system, it could use this information.  

Open question:  Should the template take priority over yum updates, or be 'merged' with yum_updates?   In general yum_updates should be able to be 'added' to the template advisories, but there is the case that a system was just assigned to a template (but was pointed to the cdn or some other template before).

• We may need to 'ignore' yum updates if the reported yum repos are not from the template
• Maybe it makes sense to just ignore yum updates as template are really meant to handle 3rd party content too.
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We could make this configurable for now incase we want to roll it back.  

We also need to make sure all systems are updated any time a template update event comes in and is processed.   Similar to what is done when vmass sync runs (creating messages for a bulk set of systems)