Add to F-Droid

[flxholle]

I created a "tracker-free" version of the dev branch, see #4
Now I'd like to add this app to F-Droid. Currently the F-Droid source code is linked on my repository but if the pull request will be merged in a new branch, I switch the link to source code.
Here is the matching merge request on GitLab for adding this app to the official F-Droid catalogue: https://gitlab.com/fdroid/fdroiddata/-/merge_requests/6915