Add OpenAPI + UI

[petrsvihlik]

https://docs.microsoft.com/en-us/aspnet/core/tutorials/web-api-help-pages-using-swagger?view=aspnetcore-5.0

[dviry]

FYI Swashbuckle is dead - dotnet/AspNetCore.Docs#31437

[petrsvihlik]

not entirely true, watch this: https://www.youtube.com/watch?v=8yI4gD1HruY

I'd go with what's in the video - Microsoft.AspNetCore.OpenApi + Scalar.AspNetCore

[dviry]

Honestly I am not even sure why you'd need an OpenApi here - those are usually done for public facing Rest services, and not for specific implementation that are only used by certrain Clients (like this one ;)

[petrsvihlik]

purely for debugging purposes...to be able to copy&paste it to postman and play around with the endpoints. a couple of times in the past, I would have appreciated if I had an easy way to check what's coming back from the checkfileinfo endpoint

[petrsvihlik]

again, low prio and a nice to have...