CUBA component that allows to pin a particular entity to a user session.
Sometimes, as a user you have to drill down your entity graph for a particular selection of a particular entity. Here's an example:
Customer --(Composition)--> Order
Now you want to select a Customer and only see all entities (in this case only the Order) with the filter for a particular customer. Basically, as a user you "pin" your Customer. Now the whole application acts as if you have only this customer in your application.
