LPS-33872 Default Site membership policy that only allows user to be a member of the site if they are also a member of the parent site

Hey Brian,

This is a default policy that we will provide with the portal.

There are somethings that I need to address for performance reasons (i.e: method verifyLimitedParentMembership()) but this is the initial version. I'll talk to Shuyang to see how we can speed this up.