Update Splashscreen and About Us dialogs for General Availability (#4901)

* Add new image for splashscreen. Layout changes incoming.

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* Adapt layouts to new splashscreen style with transparent background.

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* Ensure cropping logic works correctly when screen scaling is used.

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* Remove old image. Replace new image with new version with more readable credits.

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

Code/Editor/AboutDialog.cpp

@@ -6,10 +6,7 @@
  *
  */
 
-
-
 #include "EditorDefs.h"
-
 #include "AboutDialog.h"
 
 // Qt
@@ -47,14 +44,17 @@ CAboutDialog::CAboutDialog(QString versionText, QString richTextCopyrightNotice,
                     CAboutDialog > QLabel#link { text-decoration: underline; color: #94D2FF; }");
 
     // Prepare background image
-    m_backgroundImage = AzQtComponents::ScalePixmapForScreenDpi(
-        QPixmap(QStringLiteral(":/StartupLogoDialog/splashscreen_background_developer_preview.jpg")),
-        screen(),
-        QSize(m_enforcedWidth, m_enforcedHeight),
+    QPixmap image = AzQtComponents::ScalePixmapForScreenDpi(
+        QPixmap(QStringLiteral(":/StartupLogoDialog/splashscreen_background_2021_11.jpg")),
+        screen(), QSize(m_imageWidth, m_imageHeight),
         Qt::IgnoreAspectRatio,
         Qt::SmoothTransformation
     );
 
+    // Crop image to cut out transparent border
+    QRect cropRect((m_imageWidth - m_enforcedWidth) / 2, (m_imageHeight - m_enforcedHeight) / 2, m_enforcedWidth, m_enforcedHeight);
+    m_backgroundImage = AzQtComponents::CropPixmapForScreenDpi(image, screen(), cropRect);
+
     // Draw the Open 3D Engine logo from svg
     m_ui->m_logo->load(QStringLiteral(":/StartupLogoDialog/o3de_logo.svg"));