Provide management use cases and operations for the threading subsystem

bstansberry: ok, here's what's needed
bstansberry: 1) the subsystem needs to properly handle expressions (system props) and default values
bstansberry: 2) it needs to handle write-attribute
bstansberry: 3) the various pools expose metrics; we need to add runtime attributes for those
bstansberry: there's an overall thing too, which helps with the above
bstansberry: this week i've added some abstractions, ways to register attribute metadata and set up all the i18n properties files
bstansberry: see the ee subsystem and the first couple resources in the messaging subsystem
bstansberry: converting threads to that would be good – it's the easiest way to handle 1) above and helps with 3)

bstansberry: the EE subsystem uses what i'm talking about in a real simple way; good for grokking the basics
bstansberry: the messaging subsystem uses what i'm talking about for some metrics, so that's a useful reference too