Add progressbar to new Media details zoom activity

[neslihanturan]

Summary:
When it is a DSLR image with a big size, it took some time for it to be displayed. But user is looking at a black screen during this time. Instead there should be an progressbar.

Progressbar should appear after image from media details is clicked until image is being loaded.

[kbhardwaj123]

@neslihanturan I have understanding of the custom ZoomableDraweeView which I added to the media files so can I work on this?

[neslihanturan]

Go for it @kbhardwaj123 :)