Rename SQL Server related classes for consistency with existing Framework classes

[wilkinsona]

We have some SQL Server-related classes with names that begin with MsSqlServer or MsSql. We also have a value in the DatabaseDriver enum named SQLSERVER and there are SQL Server-related classes in Framework with names that begin with SqlServer. SqlServer also appears to be commonly used elsewhere in the ecosystem in Flyway, Hibernate, and the like. For consistency, we're going to rename Boot's SQL Server-related classes so that their names all begin with SqlServer.