Resolve "Add README documents that support the blog post"

Closes #4 (closed)

Includes an elaborate instruction of how to use cloud-init on a Greenhost VPS in the general readme, and a more elaborate instruction of how to complete the outline setup in the outline README.

I renamed "Prerequisites" in the outline and jitsi readme's because I think "requirements" is a more logical term for what I entered there. I also think every script should have at least CPU or Memory, OS and disk space under Requirements. !1 (merged) conforms to this as well FYI