Adds the BE for the new courses app...

[kevinhowbrook]

This PR is the first part of the courses work.
Designs: https://www.figma.com/file/H5pQECphbbYsvSWtag3OrCWC/Torchbox?type=design&node-id=3309-9169&mode=design&t=TxEdRwPd42H9EKdS-4

Note: This is part of a short 2 day brief that does not have any tickets created. FE will be done by Simon based of this.

Description of Changes Made

In this PR, the following is added:

• New course detail page
• 2 new block types for the course detail page
• Stubbs out the course landing page model

What's not been done:

• The pattern library is currently broken and not rendering any pages. I have not fixed (or caused) this as part of this work

How to Test

Checkout this branch locally.
Add a course landing page
Add a child course detail page.
You should be able to add everything needed for the course detail page, including the 2 new blocks.

MR Checklist

• Add a description of your pull request and instructions for the reviewer to verify your work.
• If your pull request is for a specific ticket, link to it in the description.
• Stay on point and keep it small so the merge request can be easily reviewed.
• Consider adding unit tests, especially for bug fixes. If you don't, tell us why.
• Tests and linting passes.
• Consider updating documentation. If you don't, tell us why.
• If relevant, list the environments / browsers in which you tested your changes.

[William-Blackie]

Hey @kevinhowbrook, nice work, couple of small nitpicks. ✨