Fixes Mac Console / Delegate Glitch

[josegomez]

So Avalonia registers their own App Delegate on MacOSX
See: https://github.com/AvaloniaUI/Avalonia/blob/5a2ef35dacbce0438b66d9f012e5f629045beb3d/native/Avalonia.Native/src/OSX/app.mm#L7-L23

In our application we register our own which cases Avalonia's to get removed

SQRLDotNetClient/SQRLDotNetClientUI/App.xaml.cs

Line 82 in b2463a0

NSApplication.SharedApplication.Delegate = new Platform.OSX.AppDelegate();

This causes the Avalonia registered events

- (void)applicationWillFinishLaunching:(NSNotification *)notification
{
    if([[NSApplication sharedApplication] activationPolicy] != AvnDesiredActivationPolicy)
    {
        for (NSRunningApplication * app in [NSRunningApplication runningApplicationsWithBundleIdentifier:@"com.apple.dock"]) {
            [app activateWithOptions:NSApplicationActivateIgnoringOtherApps];
            break;
        }
        
        [[NSApplication sharedApplication] setActivationPolicy: AvnDesiredActivationPolicy];
    }
}


- (void)applicationDidFinishLaunching:(NSNotification *)notification
{
    [[NSRunningApplication currentApplication] activateWithOptions:NSApplicationActivateIgnoringOtherApps];
}

To no be executed which causes our application to not be activated with the right options.

This fix basically re-implements the Avalonia events in our own AppDelegate (I just re-wrote their code in C# inside our app delegate)

This appears to fix the issue and may prevent other issues we aren't yet aware of.

I also opened this Issue with Avalonia: AvaloniaUI/Avalonia#3822 as an enhancement request.

It would be nice to be able to subscribe to all these events directly without having to re-implement the AppDelegate completely seeing as if they (Avalonia) changes or updates their delegate code our app won't benefit from that with this solution.

Either way it appears to work fine now

Also change the mac and linux installers to tar.gz #143

[alexhauser]

Great work, @josegomez!