evas/cserve2: Use scalecache with cserve2

evas/cserve2: Use scalecache with cserve2

Let's reuse the logic from scalecache and call cserve2
functions when the scalecache should be used.
So, now, cserve2 server will not scale any image... This is
too computationally intensive for the server's main thread.

This is not optimal but makes a hell of a lot more sense for
the moment. (since cserve2 manages the SHM segments)