dotnet-ef tools should support file-based apps

[jjonescz]

What problem are you trying to solve?

I have a file-based app that uses EFCore and want to be able to run dotnet ef migrations commands against it.

Originally seen here: https://makarchie.com/posts/csharp-that-looks-like-go-file-based-apps/#the-rough-edge-ef-core-migrations

Describe the solution you'd like

No response