Pass an entity ID to a form

FormBuilder allows passing of IDs for entities via URL parameters. For example, you can pass the ID of a contact via "#?Individual1=123". It would be very useful to be able to do this for a block.

An example use case is a user profile page. With the current implementation, you can set the form to autofill with the current user data. If an admin is looking at the page for a user, it will load the admin's data, not the user's data. One complexity with this use case is translating between the Drupal user ID and the Contact ID.