Remove EXIF coordinates per-picture

[nicolas-raoul]

I am happy to share EXIF coordinates of 90% of the pictures I take (landscapes, mountains, landmarks). Without EXIF coordinates these pictures would lose most of their encyclopedic/usability value.

On the other hand, I often don't want to share EXIF coordinates of the remaining 10%: Picture of a rare fruit at my friend's house, pictures of tools at a relative's workplace, pictures of super-old out-of-copyright documents at my grandmother's place, etc.

I think many contributors share the same problem.

While #181 addresses "at my home", I think we need a more case-by-case way to remove coordinates.
This could be a dedicated button on the newly-implemented coordinates modification screen.

[Ayan-10]

@nicolas-raoul I mentioned some solutions of this issue in issue #181 . Can you please give your opinion there so that I can start working on both of these issues?