💄 Switch from Swagger UI to RapiDoc

[afranke]

For a more modern interface to explore the API.

[afranke]

Before

After

Notes

• RapiDoc supports custom API servers, but getting an entry like the one we had before requires adding metadata to the spec definition. I’ll take care of that in a separate PR to the matrix-doc repository. I don’t consider this a blocker.
• I didn’t style RapiDoc with the website header/navbar on purpose because quite frankly it’s ugly in this context, gets in the way, and I doubt someone really needs to jump from the playground directly to the blog… The [matrix] logo in the top left corner is a link back to the Develop section, where visitors can then find the navbar again.
• RapiDoc supports both Swagger 2.0 and OpenAPI 3.x.x, so we won’t have to change anything when we make that move eventually.

[anoadragon453]

Some minor clarifying points, but otherwise looks good to me.

Design may want to modify the colour scheme at some point, but from your screenshot I think it looks pretty slick for a first pass (though I have no idea about accessibility for instance).