Dynamically toggle logging for Affix

[aaaaalbert]

There should be a way to dynamically enable and disable logging output on Affix components/stacks. Ideally, we would want to be able to do this separately for different deployments (production, beta, ...) and possibly single nodes.

The advertise service would be a logical place to put this information on, ideally in a signed format.

(Note: This was first documented as #1411 on the Seattle Trac.)