Atom Tools: moving custom asset browser code to common location

Consolidated duplicate asset browser code from multiple tools into single class in atom tools framework
Moved creation of asset browser and Python terminal windows into base main window class
Fixed docked window orientations
Added checks to asset browser to prevent crashes if tree state saver was null

Signed-off-by: Guthrie Adams <guthadam@amazon.com>

Gems/Atom/Tools/AtomToolsFramework/Code/Source/Window/AtomToolsMainWindow.cpp

@@ -8,6 +8,7 @@
 
 #include <AtomToolsFramework/Window/AtomToolsMainWindow.h>
 #include <AzToolsFramework/API/EditorPythonRunnerRequestsBus.h>
+#include <AzToolsFramework/PythonTerminal/ScriptTermDialog.h>
 
 #include <QFileDialog>
 #include <QMenu>
@@ -40,6 +41,11 @@ namespace AtomToolsFramework
         centralWidget->setLayout(centralWidgetLayout);
         setCentralWidget(centralWidget);
 
+        m_assetBrowser = new AtomToolsFramework::AtomToolsAssetBrowser(this);
+        AddDockWidget("Asset Browser", m_assetBrowser, Qt::BottomDockWidgetArea, Qt::Horizontal);
+        AddDockWidget("Python Terminal", new AzToolsFramework::CScriptTermDialog, Qt::BottomDockWidgetArea, Qt::Horizontal);
+        SetDockWidgetVisible("Python Terminal", false);
+
         AtomToolsMainWindowRequestBus::Handler::BusConnect();
     }