Add a pick/reject function

Within DXO Photolab I can pick/reject photos to later filter by this to be able to only show the picked ones or delete the rejected ones. This is indicated by a green or red dot within the Icon of a photo. It would be great if I could use this here in Bildhuus as well so i can do the selection here in Bildhuus and then edit them within Photolab later. So I guess this would need to be stored in the sidecard file.

Initially I assumed this was already there with little ‪‪❤️‬‪‪ Icon - but the “Favorite” function does seem to work different and is not synchronized to Photolab.