Migrate projects, primers, and paths into the curriculum repo

We're both diversifying the content of the course (so "go" in the title isn't always relevant as other languages come in). We also want to take advantage of the work we've done in the curriculum repo. So we're going to move the content from this repo to https://github.com/CodeYourFuture/curriculum (keeping in place some redirects or references as we do)

Start by inventorying the projects, primers, and paths in this repository, then compare them with the CodeYourFuture/curriculum repository. Done means the course content is migrated and the required redirects or references remain in place; the issue mentions no specific files or tests to run.

Written by the indexing model from the issue text.