Description

This PR rewrites Dynamicbeat as an independent Golang program that doesn't use libbeat. The following libraries are used to replace libbeat functionality:

• Cobra for command-line arguments
• Viper for configuration
• Zap for logging
• go-elasticsearch for ingesting check results to Elasticsearch

A change of particular note is that Dynamicbeat now ingests check results by indexing them directly to Elasticsearch, instead of passing them off to logstash for futher processing. As a result, Logstash has been removed from the Scorestack architecture.

Closes #262 - the Index Manager (or Fleet, as it now seems to be called?) would require integration with libbeat.
Closes #230 - while we don't have tests (yet!), the testsuite was part of libbeat.
Closes #81 - the fields referenced don't exist anymore.

Merge Checklist

• I have tested this change locally to make sure it works
• I have updated the documentation as necessary
• I have added a release note under the Unreleased section of the Changelog
• This PR is being merged into dev, unless it's a PR for a release