Dynamic config provider

[rkaw92]

Right now, nodeconfig only supports a single configuration provider which is only capable of one-shot operation (i.e. will never emit more than once).
At least one dynamic configuration provider needs to be implemented, where the config data is passed at arbitrary moments during run-time.
Care should be taken to ensure that the process will receive the first config package - perhaps a "poll on start" mechanism should be bundled with the provider.

Viable options for subscribing to config:

• AMQP messages with the whole config embedded
• ZeroMQ periodic broadcasts (would require config value change detection, or services will go crazy)
• redis keys containing whole config + notification on changes via pub/sub
• Filesystem + inotify (note: this is already being worked on, but using a different approach: NodeManager is a module which passes configs via ENV and restarts services when it detects config file change)