Creating standard REST API for acanban

[Huy-Ngo]

I suggest we have a standard REST API for acanban. This allows later developments to have clients different than web (e.g. native mobile or desktop clients for ability to view and submit works when offline). Even if they just intend to make another web client, it'd be easier for them to create one without having to modify the server.

However, this can be tricky regarding the authentication. REST API is based on HTTP, which is stateless. Normally, I'd go for a web token for authentication, but I am not sure how Quart-Auth handles login.

[McSinyx]

While I think it's a good idea, considering the current pace of development, I don't believe we should do it now. Doesn't hurt putting it as a TODO though I guess 🤷