add `TestScalars`

[BryanWilhite]

/// <summary>
/// Shared values for this assembly.
/// </summary>
public static class TestScalars
{
    /// <summary>
    /// The xunit category trait
    /// </summary>
    public const string XUNIT_CATEGORY = "Category";

    /// <summary>
    /// The xunit category integration test
    /// </summary>
    public const string XUNIT_CATEGORY_INTEGRATION_TEST = "Integration";

    /// <summary>
    /// The xunit category integration manual test
    /// </summary>
    public const string XUNIT_CATEGORY_INTEGRATION_MANUAL_TEST = "IntegrationManual";
}