Aggregate data for profile and contributors pages for badges

[durden]

The initial idea for this request came from @prtkgpt comment.

The main idea is that we could aggregate the guides for an author and stack to show on the contributors and profile pages. We could then use this data to have 'badges' for the number of guides published, number of guides published in a specific stack, etc.

For example, user xyz could get the 'JS contributor' badge for contributing a single guide to the javascript stack and then get something like a 'JS guru' for contributing 10+ guides to the JS stack, etc. Of course, these numbers would probably be different, but it's good for illustration of the main idea.