Refactor scenario tests to be completely metadata driven.

[MichaelSimons]

Currently the scenarios tests are defined with the following pattern:

    [Theory]
    [MemberData(nameof(GetLanguages))]
    public void VerifyClasslibTemplate(DotNetLanguage language)
    {
        var newTest = new SdkTemplateTest(
            nameof(SdkTemplateTests), language, _scenarioTestInput.TargetRid, DotNetSdkTemplate.ClassLib,
            DotNetSdkActions.Build | DotNetSdkActions.Publish);
        newTest.Execute(_sdkHelper, _scenarioTestInput.TestRoot);
    }

    [Theory]
    [MemberData(nameof(GetLanguages))]
    public void VerifyXUnitTemplate(DotNetLanguage language)
    {
        var newTest = new SdkTemplateTest(
            nameof(SdkTemplateTests), language, _scenarioTestInput.TargetRid, DotNetSdkTemplate.XUnit,
            DotNetSdkActions.Test);
        newTest.Execute(_sdkHelper, _scenarioTestInput.TestRoot);
    }

There is a fair amount of overhead/duplication with this pattern when the SdkTemplateTest constructor call is the differing logic. MemberData could be utilized to define all of this in a more metadata driven approach. Adding a new test case requires defining a single list declaring the test scenario metadata.

    [Theory]
    [MemberData(nameof(GetScenarios))]
    public void VerifyXUnitTemplate(TestScenario testScenario)
    {
        testScenario.Execute(_sdkHelper, _scenarioTestInput.TestRoot);
    }

    private static IEnumerable<TestScenario> GetScenarios()
    {
        foreach (DotNetLanguage language in Enum.GetValues<DotNetLanguage>())
        {
            yield return new(language, _scenarioTestInput.TargetRid, DotNetSdkTemplate.XUnit, DotNetSdkActions.Test),
            yield return new(language, _scenarioTestInput.TargetRid, DotNetSdkTemplate.ClassLib, DotNetSdkActions.Build | DotNetSdkActions.Publish)
        }
    }

[MichaelSimons]

cc @mattscheffer

[MichaelSimons]

Source-build utilizes this pattern in it's scenario tests