#897 - Site resolution modifications
- Make Site APIs much more specific in regards to what type of object you are getting (sometimes attached to a Session, sometimes not)
- Add an entity extension manager to contribute to the clone() method of Site
- Move the EntityExtensionManagers to be added to the BroadleafRequestContext as soon as possible
- Add EntityExtensionManagers to the BroadleafAdminRequestProcessor
- Enhance docs to call out the uniqueness in how Sites are handled