Implement first version of photo uploads

[vitalidze]

The main goal is to implement uploading of all photos in a separate thread with the following GUI behavior:

• list of photos contains only assets that haven't been uploaded yet.
• uploading initiates by tapping "Do Sync" button.
• overall progress bar appears at the bottom panel. There is an text of how many photos uploaded and how many left. In that panel there will be a "cancel" upload button with cross icon. When tapped the current and all following upload tasks are cancelled.
• every time the photo is uploaded it's marked with light gray "disabled" color in a list.
• Provide device id and name, so server can put photos to appropriate sub-folders.