Revisited attach/detach commands and how they interact with folder restrictions
Supporting item links (item links don't exist in this library - just duplicate copies of the same exact item with the same exact id, but in different folders. We will probably need to add a flag to indicate it's a linked item in the future)
Easier to differentiate between items in the shared #RLV folder and attached items that are not in the shared folder
Minor internal refactoring
Updated tests
