Re-calculate instance queue position when automated-request-queue-ordering flag is set to true

Purpose
When automated-request-queue-ordering flag is set to true the request queue is maintained on the instance level. Once the item is checked out the position of the remaining requests in the queue will need to be decreased by 1.

Scenario 1: Item is checked out
Given: the instance level queue is maintained
When: first requester check outs the item
Then: the position of the remaining requests in the queue is decreased by one

Scenario 2: Request is cancelled
Given: the instance level queue is maintained
When: a request in the queue is cancelled
Then: the position of the remaining requests in the queue is recalculated according to the request creation date

Scenario 3: Request expires
Given: the instance level queue is maintained
When: the first request in the queue expires
Then: the position of the remaining requests in the queue is recalculated according to the request creation date