GemCatalog: Gem cart widget and overlay window

* [LYN-4174] Added icons for gem catalog summary cart

* [LYN-4174] Gem Catalog: Text eliding for too long gem names and creators

* [LYN-4174] Gem catalog: Resetting filters when re-initializing for another project

* [LYN-4174] Gem Catalog: Fixed a bug with filters being applied/remembered after leaving gem catalog and coming back editing another project

* [LYN-4174] GemCatalog: Gem cart widget and overlay window

* Added cart button with dynamic label to display the number of gems to be enabled/disabled and a arrow down button to indicate some sort of pop-up/overlay window will appear on click.
* Overlay gem tags update dynamically while the dialog is open based on the gem model.
* Moved some styling from C++ to the style sheet.

Code/Tools/ProjectManager/Source/GemCatalog/GemCatalogScreen.h

@@ -14,6 +14,7 @@
 
 #if !defined(Q_MOC_RUN)
 #include <ScreenWidget.h>
+#include <GemCatalog/GemCatalogHeaderWidget.h>
 #include <GemCatalog/GemFilterWidget.h>
 #include <GemCatalog/GemListView.h>
 #include <GemCatalog/GemInspector.h>
@@ -40,6 +41,7 @@ namespace O3DE::ProjectManager
         GemListView* m_gemListView = nullptr;
         GemInspector* m_gemInspector = nullptr;
         GemModel* m_gemModel = nullptr;
+        GemCatalogHeaderWidget* m_headerWidget = nullptr;
         GemSortFilterProxyModel* m_proxModel = nullptr;
         QVBoxLayout* m_filterWidgetLayout = nullptr;
         GemFilterWidget* m_filterWidget = nullptr;