Add FromRawSql api

[RaymondHuy]

• Fix Cosmos: FromSql support #17311
• All added test cases are chosen from a subset in
  https://github.com/dotnet/efcore/blob/main/test/EFCore.SqlServer.FunctionalTests/Query/FromSqlQuerySqlServerTest.cs
• There is one considerable constraint is that: user has to include "id" column when listing all column names (in case of not using (Select *)) because of internal keys in cosmos. Not sure if this constraint can be accepted.

[smitpatel]

The FromSql for cosmos differs from relational implementation. The major difference comes in terms of materialization. Relational FromSql only consider the the SQL to provide data for the root entity type it is used on and all other related types must generate a join with it. Whereas in cosmos the definition should include all owned types in given type since aggregates are more general for Cosmos provider. This PR doesn't address above mismatch. Further most of the code seems replica of relational code, which may not be exact direction we need to take. (A point to remember is that, Relational is extended by other providers, Cosmos is not). Due to complexity of feature, I personally feel that this is not a feature where we can take a community contribution. The feature is planned for 6.0 release and as of now we intend to implement it but not through this PR.

@RaymondHuy - Thanks for attempt.