[PD-839][PD-834] Site Package Selection Improvements

I'm not sure what the desirables are for this ticket after the last UX meeting we had. It seems to me that if there are cases where site packages will be automatically generated, then we shouldn't block access to the pages that would generate said packages. I figure we can figure that out in QC and I'll make refinements then. 

For now, this does everything the original ticket asked for.