Prep for new Major release

[KristofferStrube]

In #13, we are deleting some types and some methods, which is a breaking change.

While we are making breaking changes, we should look at whether we want to remove/change other parts of the library.

Remove [Obsolete] Create methods.

We should just do this.
Finished: #15 ✅

Change to use Error Handling JSInterop from Blazor.WebIDL

This could take some time, but it greatly improves the quality of the project. We might want to consider doing the same for Blazor.Streams and Blazor.FileAPI before we do it in this project, so that most normal scenarios use Error Handling JSInterop.

If we do this, we should also add tests like we have in Blazor.MediaCaptureStreams, which can also be time-consuming.

Change FileSystemDirectoryHandle to use IAsyncIterable declaration from Blazor.WebIDL instead of implementing ValuesAsync itself.

We haven't made the IAsyncIterable decorator yet, but we have an issue for it: KristofferStrube/Blazor.WebIDL#28