Feature: Add functionality so that people can write their own reviews

[megoth]

Means putting together the various vocabularies needed to describe it (probably starting with schema.org/Review and schema.org/Rating), finding or minting some shapes for the data model, and then implement a system that allows:

1. User to write their own review
2. Store the review in their own Pod
3. Submit to have their review added to the website
4. Moderator (i.e. me) adds or disregards the review, at which the point the site will include it

This is a huge effort, so I'm gonna track thoughts and ideas here before implementing them, hopefully inviting others who might see this as a cool feature worth building.