Add Lts/Application module with Qt6 CMakeLists updates

- Copy Lts/Application from qt5-before (AarApp, OpApp, THP submodules)
- Update all CMakeLists.txt to use Qt6::Core, Qt6::Widgets, Qt6::Xml, Qt6::Network, Qt6::PrintSupport, Qt6::Svg, Qt6::WebEngineCore, Qt6::WebEngineWidgets
- No SIGNAL/SLOT, QRegExp, QDesktopWidget, or QTextCodec issues found in Application source code
- Module ready for Qt6 build validation

qt6-after/qt6-migrated-legatus/Lts/Application/THP/thpwidgets/thp_html_widget.ui

@@ -0,0 +1,49 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>HtmlWidget</class>
+ <widget class="QWidget" name="HtmlWidget">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>719</width>
+    <height>540</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string notr="true">Form</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <property name="leftMargin">
+    <number>0</number>
+   </property>
+   <property name="topMargin">
+    <number>0</number>
+   </property>
+   <property name="rightMargin">
+    <number>0</number>
+   </property>
+   <property name="bottomMargin">
+    <number>0</number>
+   </property>
+   <item>
+    <widget class="QWebEngineView" name="html">
+     <property name="url">
+      <url>
+       <string>about:blank</string>
+      </url>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <customwidgets>
+  <customwidget>
+   <class>QWebEngineView</class>
+   <extends>QWidget</extends>
+   <header location="global">QtWebEngineWidgets/QWebEngineView</header>
+  </customwidget>
+ </customwidgets>
+ <resources/>
+ <connections/>
+</ui>