fn: reorg agent config (#853)

* fn: reorg agent config

*) Moving constants in agent to agent config, which helps
with testing, tuning.
*) Added max total cpu & memory for testing & clamping max
mem & cpu usage if needed.

* fn: adjust PipeIO time
* fn: for hot, cannot reliably test EndOfLogs in TestRouteRunnerExecution

api/agent/pure_runner.go

@@ -615,6 +615,6 @@ const megabyte uint64 = 1024 * 1024
 
 func getAvailableMemoryUnits() uint64 {
 	// To reuse code - but it's a bit of a hack. TODO: refactor the OS-specific get memory funcs out of that.
-	throwawayRT := NewResourceTracker().(*resourceTracker)
+	throwawayRT := NewResourceTracker(nil).(*resourceTracker)
 	return throwawayRT.ramAsyncTotal / megabyte
 }