ZMQ Metrics by iota-prom-exporter

Added

• ZMQ metrics enabled on IRI by default
• ZMQ update procedure + iota-prom-exporter in docs
• Updated docs on how to get ZMQ metrics in IRI and graphs
• Prometheus alert rules validation added
• fpaste/cli tools to help send logs to pastebin for support/debugging

Changed

• Updated docs
• nbctl updated

Fixed

• Ansible npm not installing latest version of nelson
• nbctl breaks when empty neighbors line in configuration file