(Scene3D) Ensure remove image-resource-loader cache when app terminated

(Scene3D) Ensure remove image-resource-loader cache when app terminated

Since ImageResourceLoader use static global value internally,
it might have some problem when we use OffscreenApplication multiple time.

Since even Dali::Application destroyed, the static value can be alived.
At this time, If we create new Dali::Application one more time, the cache
system break down.

To ensure we follow up the cache system, let we connect the signal to
LifecycleController, and then delete self.
It will ensure we can re-create this cache after Dali::Application recreated.

Change-Id: I6178a91dfff2a435eb95d11e7ca8ef7479c125ed
Signed-off-by: Eunki Hong <eunkiki.hong@samsung.com>