Log the time spent working and display it in a chart

[porobidev]

Is your feature request related to a problem? Please describe. As someone who's learning web development, I'd like to know how much time I spend into this. Being able to see it directly from Pomatez would be nice since I always use pomodoro technique, so I wouldn't have to get another app.

Describe the solution you'd like Automatically log the starting and stopping time, which then you can check in a chart that shows the time spent working in a day / week / month.

Additional context Perhaps part of #100 ?