* introduce Asset as composition of AssetResponseDTO and AssetEntity
* filter out duplicate assets (that are both local and remote, take only remote for now)
* only allow remote images to be added to albums
* introduce ImmichImage to render Asset using local or remote data
* optimized deletion of local assets
* local video file playback
* allow multiple methods to wait on background service finished
* skip local assets when adding to album from home screen
* fix and optimize delete
* show gray box placeholder for local assets
* add comments
* fix bug: duplicate assets in state after onNewAssetUploaded
* properly done background backup service
* new concurrency/locking management with heartbeat
fix communication erros with Kotlin plugin on start/stop service methods
better error handling for BackgroundService public methods
Add default notification message when service is running
* configurable WiFi & charging requirement for service
* use translations in background service
* Fixed app not resuming backup after closing and reopening the app
* Fixed cosmetic effect of backup button doesn't change state right away after pressing start backup
* Fixed grammar
* Fixed deep copy problem that cause incorrect asset count when backing up
* Format code
