Simplify xidlehook logic significantly

[jD91mZM2]

https://gitlab.com/jD91mZM2/xidlehook/-/merge_requests/9

K.I.S.S.

Is this sane?

I'm losing my sanity over all the features this thing needs, and at this point I don't think there exists an optimal algorithm that sleeps the longest possible. I tried, I really tried, but the truth is the user could cause activity at any point, and timers can be enabled/disabled at any point, and that combination means a timer that is in the middle of everything could in theory be activated by all other timers disabling and the user could go active and then idle again and it could be triggered.

Don't merge this on GitHub. GitLab is the primary repository, but I'm posting it here so more people can see it.