Similar to the rebind functionality that lets you rename parameters
from those in the store, inject lets you inject arbitrary key/value
pairs that will be sent to your task at task creation time. This allows
for flow and flow factories to reuse tasks with differing parameters
without jumping through a lot of hoops.
Change-Id: If167962811d22054b89d7d35a33d4ec5cb2cd648
Implements: blueprint wbe-workers-endpoints-constructors
46fc1dd9ee