Create blueprints section and guidance in website #238
Description
Create a new section under https://opentelemetry.io/docs/ for blueprints. This should be under a top-level Guidance and Architecture section, with the idea of having a Blueprints and Reference Architecture sections under that.
Along with the creation of section, we should add a few paragraphs on what blueprints are, and point to the process of proposing/creating a new blueprints, which should be discussed as part of this issue.