Create a new automated test for Prefab basic workflows (#2715)

Adds a new ebus for prefab apis and refactored the apis
Removed an empty test level
Auto delete tmp level when teardown tests
Add Base test level in Prefab folder
Removed unused comments
Checked if absolute path as an input of Create Prefab functions
Changed created prefab file path to support all platfroms
Added missing includes

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

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabSystemComponent.h

@@ -24,6 +24,7 @@
 #include <AzToolsFramework/Prefab/PrefabIdTypes.h>
 #include <AzToolsFramework/Prefab/PrefabLoader.h>
 #include <AzToolsFramework/Prefab/PrefabPublicHandler.h>
+#include <AzToolsFramework/Prefab/PrefabPublicRequestHandler.h>
 #include <AzToolsFramework/Prefab/PrefabSystemComponentInterface.h>
 #include <AzToolsFramework/Prefab/Template/Template.h>
 
@@ -369,6 +370,9 @@ namespace AzToolsFramework
 
             // Used for updating Templates when Instances are modified
             InstanceToTemplatePropagator m_instanceToTemplatePropagator;
+
+            // Handler of the public Prefab requests
+            PrefabPublicRequestHandler m_prefabPublicRequestHandler;
         };
     } // namespace Prefab
 } // namespace AzToolsFramework