SqlDatabaseFileGroup: New resource suggestion

Details of the scenario you tried and the problem that is occurring:
I suggest we add a resource named SqlDatabaseFileGroup to be able to create and remove filegroups, which in turn can be used by the suggested resource SqlDatabaseFile (issue #57).

The properties to be set for a file group can be seen in this article ALTER DATABASE (Transact-SQL) File and Filegroup Options.

Suggested schema for discussion below.

[ClassVersion("1.0.0.0"), FriendlyName("SqlDatabaseFileGroup")]
class MSFT_SqlDatabaseFileGroup : OMI_BaseResource
{
    [Key, Description("The name of the database to be configured.")] String DatabaseName;
    [Key, Description("The host name of the SQL Server to be configured.")] String SQLServer;
    [Key, Description("The name of the SQL instance to be configured.")] String SQLInstanceName;
    [Key, Description("The name of the filegroup.")] String Name;
    [Write, Description("An enumerated value that describes if the filegroup should be added ('Present') or removed ('Absent'). Default value is 'Present'."), ValueMap{"Present","Absent"}, Values{"Present","Absent"}] String Ensure;
    [Write, Description("Set to $true if the filegroup should be the default filegroup. Only one filegroup in the database can be the default filegroup. Defaults to $false.")] Boolean Default;
    [Write, Description("If set to $true specifies that the filegroup stores FILESTREAM binary large objects (BLOBs) in the file system. Defaults to $false.")] Boolean FileStream;
    [Write, Description("If set to $true specifies that the filegroup stores memory optimized data in the file system. Defaults to $false.")] Boolean MemoryOptimizedData;
    [Write, Description("Sets what happens when a filegroup reaches the autogrow threshold. If set to 'Single' means when a file in the filegroup meets the autogrow threshold, only that file grows. If set to 'All' means when a file in the filegroup meets the autogrow threshold, all files in the filegroup grow. Default is 'Single'."), ValueMap{"Single","All"}, Values{"Single","All"}] String AutoGrow;
};

The DSC configuration that is using the resource (as detailed as possible):
n/a

Version of the Operating System, SQL Server and PowerShell the DSC Target Node is running:
n/a

What module (SqlServer or SQLPS) and which version of the module the DSC Target Node is running:
n/a

Version of the DSC module you're using, or 'dev' if you're using current dev branch:
n/a

Review the proposed schema and the linked ALTER DATABASE (Transact-SQL) File and Filegroup Options article, then compare the existing SqlServerDsc resource conventions. Issue #57 provides related context for SqlDatabaseFile. Done means the module supports a SqlDatabaseFileGroup resource that can create and remove filegroups with the proposed properties.