AppContext and *CompatibilityPreferences infrastructure

[vatsan-madhavan]

This PR brings up a functioning infrastructure for AppContext and *CompatibilityPreferences infrastructure.

• AppContext based quirks would be set in runtimeconfig.template.json
• I haven't tested to verify whether these support registry.
• *CompatibilityPreferences would continue being set in App.config

The new defaults for various quirks are so:

{
  "configProperties": {
    /*
    // BuildTasksAppContextSwitches
    "Switch.System.Windows.Markup.DoNotUseSha256ForMarkupCompilerChecksumAlgorithm": false,

    // CoreAppContextSwitches
    "Switch.System.Windows.DoNotScaleForDpiChanges": false,
    "Switch.System.Windows.Media.ImageSourceConverter.OverrideExceptionWithNullReferenceException": false,
    "Switch.System.Windows.DoNotUsePresentationDpiCapabilityTier2OrGreater": false,
    "Switch.System.Windows.Input.Stylus.DisableStylusAndTouchSupport": false,
    "Switch.System.Windows.Input.Stylus.EnablePointerSupport": false,
    "Switch.System.Windows.Diagnostics.DisableDiagnostics": false,
    "Switch.System.Windows.Diagnostics.AllowChangesDuringVisualTreeChanged": false,
    "Switch.System.Windows.Input.Stylus.DisableImplicitTouchKeyboardInvocation": false,
    "Switch.System.Windows.Media.ShouldRenderEvenWhenNoDisplayDevicesAreAvailable": false,
    "Switch.System.Windows.Media.ShouldNotRenderInNonInteractiveWindowStation": false,
    "Switch.System.Windows.DoNotUsePresentationDpiCapabilityTier3OrGreater": false, // Reserved for future use
    "Switch.System.Windows.AllowExternalProcessToBlockAccessToTemporaryFiles": false,
    "Switch.System.Windows.EnableLegacyDangerousClipboardDeserializationMode": false,

    // FrameworkAppContextSwitches
    "Switch.System.Windows.Controls.Text.UseAdornerForTextboxSelectionRendering": true,
    "Switch.MS.Internal.DoNotApplyLayoutRoundingToMarginsAndBorderThickness": false,
    "Switch.System.Windows.Controls.Grid.StarDefinitionsCanExceedAvailableSpace": false,
    "Switch.System.Windows.Controls.TabControl.SelectionPropertiesCanLagBehindSelectionChangedEvent": false,
    "Switch.System.Windows.Data.DoNotUseFollowParentWhenBindingToADODataRelation": false,
    "Switch.System.Windows.Data.Binding.IListIndexerHidesCustomIndexer": false,
    "Switch.System.Windows.Baml2006.AppendLocalAssemblyVersionForSourceUri": false,
    "Switch.System.Windows.Controls.KeyboardNavigationFromHyperlinkInItemsControlIsNotRelativeToFocusedElement": false,
    "Switch.System.Windows.Automation.Peers.ItemAutomationPeerKeepsItsItemAlive": false,

    // BaseAppContextSwitches
    "Switch.MS.Internal.DoNotUseCulturePreservingDispatcherOperations": false,
    "Switch.MS.Internal.UseSha1AsDefaultHashAlgorithmForDigitalSignatures": false,
    "Switch.MS.Internal.DoNotInvokeInWeakEventTableShutdownListener": false,
    "Switch.MS.Internal.EnableCleanupSchedulingImprovements": false,
    "Switch.MS.Internal.EnableWeakEventMemoryImprovements": false,

    // AccessibilitySwitches
    "Switch.UseLegacyAccessibilityFeatures": false,
    "Switch.UseLegacyAccessibilityFeatures.2": false,
    "Switch.UseLegacyAccessibilityFeatures.3": false,
    "Switch.UseLegacyToolTipDisplay": false,
    "Switch.System.Windows.Controls.ItemsControlDoesNotSupportAutomation": false
  */
  }
}

<configuration>
  <appSettings>
    <!-- Defined in CoreCompatibilityPreferences -->
    <!-- 
    <add key="IsAltKeyRequiredInAccessKeyDefaultScope" value="false"/>
    <add key="EnableMultiMonitorDisplayClipping" value="null"/>
    <add key="IncludeAllInkInBoundingBox" value="true"/>
    -->
    
    
    <!-- Defined in BaseCompatibilityPreferences -->
    <!-- 
    <add key="ReuseDispatcherSynchronizationContextInstance" value="false"/>
    <add key="FlowDispatcherSynchronizationContextPriority" value="true"/>
    <add key="InlineDispatcherSynchronizationContextSend" value="true"/>
    <add key="HandleDispatcherRequestProcessingFailure" value="Continue"/>
    <add key="MatchPackageSignatureMethodToPackagePartDigestMethod" value="true"/>
    -->
    
    <!-- Defined in FrameworkCompatibilityPreferenes -->
    <!-- 
    <add key="AreInactiveSelectionHighlightBrushKeysSupported" value="true"/>
    <add key="KeepTextBoxDisplaySynchronizedWithTextProperty" value="true"/>
    <add key="ShouldThrowOnCopyOrCutFailure" value="false"/>
    <add key="HandleTwoWayBindingToPropertyWithNonPublicSetter" value="Allow"/>
    <add key="UseSetWindowPosForTopmostWindows" value="false"/>
    <add key="VSP45Compat" value="false"/>
    -->
  </appSettings>
</configuration>

Also see microsoft/WPF-Samples#87

[rladuca]

Looks good. All the defaults seem correct.