Add catalog courses

## Description

Ref: https://github.com/freeCodeCamp/freeCodeCamp/blob/main/packages/shared/src/config/catalog.ts

I haven't looked closely at the query structure, but I imagine it would look something like this:

- Overview

```graphql
query {
curriculum {
superblocks
certifications
catalog
}
}
```

or

```graphql
query {
catalog {
courses
}
}
```

- Detail (not sure if we need to separate `course` and `block`)

```graphql
query {
course(dashedName: "learn-python-for-beginners") {
title
level
topic
duration
}
}
```