State the difference between Play store version and FOSS version in README

[rickymohk]

I installed this app from F-droid and cannot see how to do auto background removal while the app UI and github readme both claim it has this feature. I was confused until I go to telegram and searched for the answer. It would be great if the difference between Play store version and FOSS version is clearly stated on the readme page. It would also be better if the app UI reflect the difference (i.e. don't say there is an auto background removal option when there isn't in the FOSS version)