Enhancement: extend ruby-runtime build logic to add test to see if .bonsai.yml conforms with sensu-ruby-runtime supported platform list

[jspaleta]

This may need some work inside sensu-ruby-runtime as well.

The idea here is to make it possible to build CI automation that tests .bonsai.yml
to see if its build definitions conform to sensu-ruby-runtime's current sets of builds.

Implement:

• build conformance test script that can be run manually and errors out CI builds
• helper script to re-build conformant .bonsai.yml