Update categories to use the latest Open Eligibility taxonomy

[monfresh]

Now that categories have slugs with history, and since categories are set based on slug, I think we can safely update the names without affecting existing data. I will test thoroughly first of course 😄

[monfresh]

Just a note that my comment above from early this year is no longer valid. When updating categories by writing to the API, you pass in an array of oe_ids, not slugs. In the admin interface, whether or not a checkbox is checked is based on the oe_id, but what gets submitted in the form is the DB id of the category.