Add Initial Gem Repository Management Screen (#4172)

* Adds the gem repo screen with the UI built but with mocked data and not connected to the o3de scripts

Signed-off-by: nggieber <nggieber@amazon.com>

* Changed name of added to enabled, disabled define, removed unused functions

Signed-off-by: nggieber <nggieber@amazon.com>

* Added eof nl to qss

Signed-off-by: nggieber <nggieber@amazon.com>

Code/Tools/ProjectManager/Source/ScreenFactory.cpp

@@ -13,7 +13,9 @@
 #include <GemCatalog/GemCatalogScreen.h>
 #include <ProjectsScreen.h>
 #include <UpdateProjectSettingsScreen.h>
+#include <EngineScreenCtrl.h>
 #include <EngineSettingsScreen.h>
+#include <GemRepo/GemRepoScreen.h>
 
 namespace O3DE::ProjectManager
 {
@@ -41,9 +43,15 @@ namespace O3DE::ProjectManager
         case (ProjectManagerScreen::UpdateProjectSettings):
             newScreen = new UpdateProjectSettingsScreen(parent);
             break;
+        case (ProjectManagerScreen::Engine):
+            newScreen = new EngineScreenCtrl(parent);
+            break;
         case (ProjectManagerScreen::EngineSettings):
             newScreen = new EngineSettingsScreen(parent);
             break;
+        case (ProjectManagerScreen::GemRepos):
+            newScreen = new GemRepoScreen(parent);
+            break;
         case (ProjectManagerScreen::Empty):
         default:
             newScreen = new ScreenWidget(parent);