Track heap & native (!) memory usage logs

skitt and I had a discussion today how to best proceed on the parent issue, and AFTER the other two sub tasks have been clarified, would like to see more details about the evolution of both heap and native memory usage of this JVM in this scenario.

There are a couple of ways this could be obtained:

1. using a JMX client such as VisualVM or Java Mission Control
2. using Apache Karaf Decanter, need INTDIST-95
3. using collectd, see e.g. Sai's blog ?
4. using some custom ODL code that just logs - I'll try something in infrautils, see INFRAUTILS-19 and INFRAUTILS-20