Move queue/meter/flow listeners into their trackers

This completes the move of triggers under a per-node registration. With
this structure we should have a complete control of what should be going
on for a switch.

Change-Id: Ia35c925947e044ff826c1f2560c040fe696aaed0
Signed-off-by: Robert Varga <rovarga@cisco.com>
Merge "Move queue/meter/flow listeners into their trackers"