Improve cmake and GUI (#13)

+ Packaging and CI for Windows, Mac, Linux
+ Debian package, NSIS Windows installer, OSX appbundle
+ Example application using libqtk
+ Component installation for `qtk`, `libqtk`, or `collection` with cmake

example-app/main.cpp

@@ -0,0 +1,22 @@
+/*##############################################################################
+## Author: Shaun Reed                                                         ##
+## Legal: All Content (c) 2023 Shaun Reed, all rights reserved                ##
+## About: Example Qt desktop application using Qtk                            ##
+##                                                                            ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0   ##
+##############################################################################*/
+
+#include <QApplication>
+#include <QMainWindow>
+
+#include "examplewidget.h"
+
+int main(int argc, char * argv[]) {
+  QApplication app(argc, argv);
+
+  auto window = new QMainWindow;
+  window->setCentralWidget(new ExampleWidget);
+  window->show();
+
+  app.exec();
+}