Gear groups should timeout aggressively when fetching state

The gear group state call needs to time out more quickly on absent gears.  Set
default to 10s, and allow clients to request a specific timeout via the API. 
Verified that partial results are returned.  UI will use 3 second timeout, and
show 'unknown' for any that have not returned yet.

Also, exclude quota checking from app-state-show because it is not intended to
be read by clients and because it is a performance critical path

@jwhonce @danmcp review please