Removed plugin from store

[kevinpapst]

Hello 🍄

I appreciate your work here and that you share your code publicly.
Unfortunately nobody ever took over this plugin and I do not want to feature a plugin, that hasn't received a commit in 5 years, so in order to keep the store "clean" I removed this plugin now.

If you are going to maintain it again, you can revert this commit in the website repo and send a PR to merge it again:
kimai/www.kimai.org@c270718

In the meantime there is a plugin, that allows to share project statistics via hidden links and with optional password protection:
https://www.kimai.org/store/customer-portal.html