Redo the image viewer, again

[klinker24]

This is a really cool little demo: https://github.com/iammert/DragToDismissImageViewer

Similar to Google Photos. I would love to update Talon's image viewer to use this type of style. What do I do when there are multiple images though? Hmm.

Google Photos just starts this style with a vertical swipe. Talon could do the same

Todo:

• [x] Implement this on the ImageViewerDialog
• [x] Implement this on the ImagePagerDialog
• [x] Try again at providing shared element transitions (also on the pager, not just the individual images)

[klinker24]

I started a branch. Some quick todo (definitely not an exhaustive list):

• [x] ~allow swiping from left to right to close when there is only one picture~ not doing this
• [x] add the share, info, ect back to the activity
• [x] fix the share element tranitions
• [x] fix zooming to go full screen (pull the activity from the old image viewer)
• [x] allow for swiping between images
• [x] scale down the image as the alpha goes down
• [x] major cleanup and refactoring