Add `vorta for bogbackup` icon for system-tray.

[soymadip]

like kup of kde project, Vorta is a backup software based on BorgBackup.

but as of now this theme doesn't have the system tray icon for the app so the app looks very weird:

It would be pretty cool to have a system tray icon for that app. as a suggestion i would like to say that the kup icon will be cool for that too.