[Feature] Hook scripts

[Nachasic]

I would like to script some actions, depending on my activity status for habit management. For example, if I'm procrastinating, I could send a notification to myself to start a pomodoro timer.

Possible solution

Add a property to each activity called scripts that sets a path to a collection of shell scripts:

[[activity]]
name = "rtrackr"
productivity = 1
scripts = "~/activities/rtrackr/"

[[activity.rule]]
# ...

All relative path are considered relative to $XDG_DATA_HOME.

The program then looks for shell scripts in the folder, following a naming convention [status]-[delay-in-seconds]-Script_name.sh, example:

AFK-15-Get_back_to_work_notification.sh
AFK-30-Do_some_pushups_lock.sh

These scripts can send me notifications, kill my browser or even lock my session if I want them to.