Get records API route

[qdm12]

• JSON marshal settings for each provider
• Setup route GET /api/v1/records
• Unit test for HTTP handler with an example record
• Document API routes in readme for now. Maybe add swagger later ❓
• Add auth as this introduces a security hole otherwise. Force auth to access this route

Working on a (Flutter 2) UI to consume it, that should be a first step to have a 'dynamic' new UI with the same features as the current one.

[fredericrous]

should you not return here?

[qdm12]

No, this is just sending an http response as json {"error": "message"} with the status code given 😉
I'll get to authentication soon to merge that.

[fredericrous]

fair point 🤣. I reviewed the rest, all seem alright to me. I learnt about Read Locks, it seemed weird to me to have to lock in order to read. Regarding authentication, a cool thing could be to make ddns-updater a microservice that implements oauth2. We could interface it with the user management interface we want, we wouldn't have to maintain user management. I'm personally using Authelia which has oauth2 in beta. There is also https://github.com/netlify/gotrue