Edit documentation to improve clarity
Edit documentation to improve clarity

This commit simplifies a few complex sentences, adds a few section
headers, and makes the presentation of the YAML options more consistent.

signalfuse/maestro-ng,signalfuse/maestro-ng,signalfx/maestro-ng,zsuzhengdu/maestro-ng,zsuzhengdu/maestro-ng,signalfx/maestro-ng