Modify FunSqlExpr (DML) to support qualified names (ms-sql server)

[kahlil29]

Currently FunSqlExpr is defined in DBRecord.Internal.Sql.DML as
FunSqlExpr String [SqlExpr] where the first argument (name) is a String.

In ms-sql server, we can have function names like [dbo].[CheckFunc].
In order to support this, we need to change the format and allow a different structure that would let us store the qualifier as well as the function name.