Database context factory registration for EF core database components

[a2er]

It would be great to have an extension method equal to AddSqlServerDbContext for registering EF core database components with AddPooledDbContextFactory or AddDbContextFactory.

[eerhardt]

In preview4 we've added a new API to the EF core database components that allows you to register the DbContext as you normally do, and then "enrich" it with extra Aspire services/configuration. See #1403 and #2125.

So now you can call builder.Services.AddPooledDbContextFactory<MyDbContext>(...) as usual, and then afterwards call builder.EnrichNpgsqlDbContext<MyDbContext>();.