Open CMake GUI from Project Manager (#4360)

This provides a fast way for engineers who want to configure -> generate -> open project in IDE -> build & run to do so without waiting for a potentially lengthy Project Manager build.

Signed-off-by: AMZN-alexpete <26804013+AMZN-alexpete@users.noreply.github.com>

Code/Tools/ProjectManager/Source/ProjectUtils.h

@@ -42,6 +42,8 @@ namespace O3DE::ProjectManager
             int commandTimeoutSeconds = ProjectCommandLineTimeoutSeconds);
 
         AZ::Outcome<QProcessEnvironment, QString> GetCommandLineProcessEnvironment();
+        AZ::Outcome<QString, QString> GetProjectBuildPath(const QString& projectPath);
+        AZ::Outcome<void, QString> OpenCMakeGUI(const QString& projectPath);
 
     } // namespace ProjectUtils
 } // namespace O3DE::ProjectManager