Moved Cache $content collection to Element

[zeroasterisk]

The Cache details only included all the Model & Controller level Caches

that is, it contained all Cache utilization until the beforeRender() callback

Now, it will also include all the Cache utilization during the render process (until this element is rendered) which means it should get all Application Views/Helpers/Elements too.

(NOTE: the title of the tab will not be accurate with the extra details from View/Rendering)