Add support for the salary privilege in the privilege handler.
Implement associated logic to process and validate the
salary privilege in the test cases. Update the data
structures to include the new privilege and ensure
correct functionality in the privilege processing flow.
Adds a Setup method to PrivilegeHandler that configures AMQP consumers
for user and privilege events. This enables the handling of User.Added,
User.Removed, Privilege.Added, and Privilege.Removed events in a
streamlined manner, enhancing the event-driven capabilities of the
handler.