Extend the list of required memory related metrics

[siruslan]

At the moment only Heap (Used, Committed, Max) metrics are mandatory, but very often JVM consumes significant amount of memory in non-heap area. It's possible to get this data via same MBean approach. I suggest to extend the required metrics with NonHeap (Used, Committed, Max) information.

Also, there is a required cpu.availableProcessors. Then it makes sense to add os.memoryTotal based on Runtime.getRuntime().totalMemory().