[LYN-4437] Replaced the background images for the Project Manager

* Added the two new background images.
* Background is now dynamically changing based on whether the user opens the PM the first time or has already created a project.

Signed-off-by: Benjamin Jillich <jillich@amazon.com>

Code/Tools/ProjectManager/Resources/Backgrounds/DefaultBackground.jpg

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:342c3eaccf68a178dfd8c2b1792a93a8c9197c8184dca11bf90706d7481df087
+size 1611268

Code/Tools/ProjectManager/Resources/Backgrounds/FirstTimeBackgroundImage.jpg

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:7088e902885d98953f6a1715efab319c063a4ab8918fd0e810251c8ed82b8514
-size 542983

Code/Tools/ProjectManager/Resources/Backgrounds/FtueBackground.jpg

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:797794816e4b1702f1ae1f32b408c95c79eb1f8a95aba43cfad9cccc181b0bda
+size 1135182

Code/Tools/ProjectManager/Resources/ProjectManager.qrc

@@ -26,12 +26,13 @@
         <file>o3de.svg</file>
         <file>menu.svg</file>
         <file>menu_hover.svg</file>
-        <file>Backgrounds/FirstTimeBackgroundImage.jpg</file>
         <file>ArrowDownLine.svg</file>
         <file>ArrowUpLine.svg</file>
         <file>CarrotArrowDown.svg</file>
         <file>Summary.svg</file>
         <file>WindowClose.svg</file>
         <file>Warning.svg</file>
+        <file>Backgrounds/DefaultBackground.jpg</file>
+        <file>Backgrounds/FtueBackground.jpg</file>
     </qresource>
 </RCC>

Code/Tools/ProjectManager/Source/ProjectsScreen.cpp

@@ -53,8 +53,6 @@ namespace O3DE::ProjectManager
         vLayout->setContentsMargins(s_contentMargins, 0, s_contentMargins, 0);
         setLayout(vLayout);
 
-        m_background.load(":/Backgrounds/FirstTimeBackgroundImage.jpg");
-
         m_stack = new QStackedWidget(this);
 
         m_firstTimeContent = CreateFirstTimeContent();
@@ -232,6 +230,8 @@ namespace O3DE::ProjectManager
             m_projectsContent->deleteLater();
         }
 
+        m_background.load(":/Backgrounds/DefaultBackground.jpg");
+
         // Make sure to update builder with latest Project Button
         if (m_currentBuilder)
         {
@@ -459,6 +459,7 @@ namespace O3DE::ProjectManager
     {
         if (ShouldDisplayFirstTimeContent())
         {
+            m_background.load(":/Backgrounds/FtueBackground.jpg");
             m_stack->setCurrentWidget(m_firstTimeContent);
         }
         else