Support the new BCL DateOnly and TimeOnly structs for SQL Server

[roji]

New DateOnly and TimeOnly structs are being introduced to .NET 6 as alternatives to DateTime (dotnet/runtime#49036). This issue tracks supporting them in SQL Server.

I've opened a separate SqlClient issue for support (dotnet/SqlClient#1009).

[mattjohnsonpint]

Please note that the final names for these types are DateOnly and TimeOnly and that they are now merged into the main branch for the next version of .NET 6 (preview 4 likely). Please rename the title of this issue accordingly. Thanks.

[roji]

Clearing milestone to discuss doing this in 6.0.0.

[mattjohnsonpint]

DateOnly and TimeOnly should map cleanly to SQL Server's date and time types. The tricky part will be to decide what to do with existing behavior that maps them to DateTime and TimeSpan. They should continue to function, but the new types should be preferred for things like scaffolding.

[CleanCodeX]

As of NET 6 Preview 6 I get an error using EF Core mapping DateOnly properties stating that the DB Provider (SQL Server) does not support this type. Is it supported or not? If not, can HaveConversion be a workaround? so far nothing worked (except not using DateOnly).