* refactor serving file function asset service
* Remove PhotoViewer for now since it creates a problem in 2.10
* Added error message for wrong decode file and logo for failed to load file
* Fixed error when read stream cannot be created and crash server
* Added method to get all assets as a raw array
* Implemented cleaner way of grouping image
* Implemented operation to delete assets in the database
* Implemented delete on database operation
* Implemented delete on device operation
* Fixed issue display wrong information when the auto backup is enabled after deleting all assets
