Zoom capability in gallery mode

[kirillt]

Previews of image resources must be possible to zoom-in.

[kirillt]

After brief experimentation (https://github.com/vio123/ark-navigator/tree/146661e54d116ab8bf599846784007057a7731d4) the following things brought my interest:

• TouchImageView seems to be correct in terms of functionality
• when used with Glide it can cause white screen instead of loaded picture
• huge images can cause slow-down when loaded improperly
• zooming must trigger entering into full-screen mode
• when a picture is zoomed-in, we should block or make it harder to scroll between pictures

These points are very high-level and require deeper investigation.

[kirillt]

If image loading needs to be separated into low-res and high-res parts and high-res loads too slow, spinner animation should be drawn on top of low resolution image