libappimage 1.0.0 produces duplicate menu entries, doesn't clean up old ones

[TheAssassin]

libappimage 1.0.0 has changed the algorithm to determine the installed desktop file's path. Therefore, when using tools which use the old and new version in parallel (or after an upgrade), you get tons of duplicate entries. The old ones can't be auto-cleaned-up, since the files they point to still exist.

I don't know why this change was conducted, and I don't think we should invest too much time into reverting this, since there's no tools left really that use the old stuff. This issue is more of a note for people looking into the reasons why this happens.

Note for future: never ever change existing algorithms like this. If you have to, make sure you implement some code to avoid situations like the one I described above. This always leads to issues. For instance, I had to rm ~/.local/share/applications/appimagekit_*.desktop and then re-integrate all my AppImages. Really annoying.