iRODS 5: Implement setup and teardown plugin operations

[alanking]

From irods/irods@aefe05f.

Rule Engine plugin operations:

    Rule Engine plugins must now implement two new operations:

        - setup
        - teardown

    These operations were introduced as a way to control when a plugin's
    configuration is loaded.

    Static configuration should be moved from the start operation to
    setup.

    setup and teardown are executed during agent factory initialization
    and shutdown. These operations are executed one time for the
    lifetime of the agent factory. Agents never invoke these operations.