Add dynamic rate limit blueprint

[davidmytton]

Add a blueprint for the video we already have showing off dynamic rate limits using Prisma.

[luigimorel]

@davidmytton could you specify what is required and the success criteria?

[davidmytton]

We don't have a spec yet, so this would be taking the Prisma example + video and converting it into a blueprint. This should include explanation of how it interacts with the settings stored in the database via Prisma.