Refactor build system and UI

+ Install configs for Qt Designer plugins and Qtk application
+ Add Qtk plugin collection for Qt Designer
+ QtkWidget plugin
+ TreeView widget plugin
+ DebugConsole widget plugin
+ All widgets are fully integrated with Qt Designer
+ All widgets can be popped out or docked within the window
+ All widgets can be stacked to use tab view for side panels
+ All widgets can be toggled on/off through the view context menu
+ QtkWidget debug console
+ QtkWidget active scene TreeVew
+ QtkWidget dockable tool bar
+ Double-click an object name in the TreeView to focus camera
+ Separate libaray from widgets

There is still a lot to do here, but the major refactoring should be
done after this commit. Some of the new features were put together as
POC for working with the new UI. A few placeholder buttons were added
that have no functionality.

src/app/widgetplugin.cpp

@@ -0,0 +1,88 @@
+/*##############################################################################
+## Author: Shaun Reed                                                         ##
+## Legal: All Content (c) 2022 Shaun Reed, all rights reserved                ##
+## About: Generic Qt Designer widget plugin                                   ##
+##                                                                            ##
+## Contact: shaunrd0@gmail.com  | URL: www.shaunreed.com | GitHub: shaunrd0   ##
+################################################################################
+*/
+
+#include <QIcon>
+#include <QtPlugin>
+#include <utility>
+
+#include "qtk/qtkapi.h"
+
+#include "widgetplugin.h"
+
+WidgetPlugin::WidgetPlugin(
+    QString group, QString class_name, QString include,
+    WidgetPlugin::Factory factory) :
+    m_group(std::move(group)),
+    m_className(std::move(class_name)), m_includeFile(std::move(include)),
+    m_factory(std::move(factory)), m_objectName(class_name) {}
+
+QString WidgetPlugin::toolTip() const {
+  return QStringLiteral("A custom widget tool tip.");
+}
+
+QString WidgetPlugin::whatsThis() const {
+  return QStringLiteral("Custom widget what's this?");
+}
+
+QIcon WidgetPlugin::icon() const {
+  return Qtk::getIcon();
+}
+
+bool WidgetPlugin::isContainer() const {
+  return true;
+}
+
+QString WidgetPlugin::group() const {
+  return m_group;
+}
+
+QString WidgetPlugin::name() const {
+  return m_className;
+}
+
+QString WidgetPlugin::includeFile() const {
+  return m_includeFile;
+}
+
+QWidget * WidgetPlugin::createWidget(QWidget * parent) {
+  return m_factory(parent);
+}
+
+bool WidgetPlugin::isInitialized() const {
+  return m_initialized;
+}
+
+void WidgetPlugin::initialize(QDesignerFormEditorInterface *) {
+  if(m_initialized) {
+    return;
+  }
+
+  m_initialized = true;
+}
+QString WidgetPlugin::domXml() const {
+  return
+      "<ui language=\"c++\">\n"
+       " <widget class=\"" + m_className + "\" name=\"" + m_objectName + "\">\n"
+       "  <property name=\"geometry\">\n"
+       "   <rect>\n"
+       "    <x>0</x>\n"
+       "    <y>0</y>\n"
+       "    <width>100</width>\n"
+       "    <height>100</height>\n"
+       "   </rect>\n"
+       "  </property>\n"
+       "  <property name=\"toolTip\" >\n"
+       "   <string>" + toolTip() + "</string>\n"
+       "  </property>\n"
+       "  <property name=\"whatsThis\" >\n"
+       "   <string>" + whatsThis() + "</string>\n"
+       "  </property>\n"
+       " </widget>\n"
+       "</ui>\n";
+}