Switch autoscaler metrics to something real

[mattmoor]

Today the //cmd/autoscaler emits a number of metrics via log statements that we can lazily parse via awk.

It should instead publish metrics in a way that they can integrate with our monitoring apparatus.

@mdemirhan @josephburnett I suspect that this would be a useful exercise for someone new to either autoscaling or monitoring, so I'm tagging it as such. If you could add some more substance and pointers I'd appreciate it. :)

[markusthoemmes]

Seems to be fixed as well (not closed by the auto-close on github)

[mdemirhan]

Yes, this is fixed. I will now close the issue. Thanks for reminding!