runctl: support patching metrics in dynamically

WIP, see
- https://github.com/strongloop/strongops/pull/198
- https://github.com/strongloop/strong-agent-statsd/pull/5
/to @chandadharap  @crandmck  what should this say?

Metrics (and the patch sub-command) don't work without a license, I should say how to get one, what is verbage, please?