Added Menu to Gem Catalog with Action to Navigate to Gem Repo Screen (#4829)

* Added menu to Gem Catalog that with option to navigate to Gem Repo screen

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

* Changed Goto to GoTo and added a tr

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

* Gem repo button works from new project creation workflow as well and users are warned if they have pending changes in the gem catalog before changing screens.

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

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

@@ -41,7 +41,11 @@ namespace O3DE::ProjectManager
         GemModel* GetGemModel() const { return m_gemModel; }
         DownloadController* GetDownloadController() const { return m_downloadController; }
 
+    private slots:
+        void HandleOpenGemRepo();
+
     private:
+
         void FillModel(const QString& projectPath);
 
         GemListView* m_gemListView = nullptr;