[FEATURE_REQUEST] Subjets field

[ghost]

Book subjects on OpenLibrary aren’t as straightforward as a few genre tags so I don’t know what would be the best way to implement this on the app but it would be great to have that field as another way to filter books.
It can be argued that the tags field is enough for this but it doesn’t add the subjects automatically and besides it’s just a different purpose and using the same field is like having Notes and Review merged