Filter monthly tracking time by instrument

I play 2 instruments and would like to track how much time I practiced for each instrument monthly. Currently, the app sums the practice time of both instruments together so I am unable to track how I do with one or the other!

Yes it makes a lot of sense! :)

Merged "Allow users to see practice hours by instrument" #573

"Please add a way for me to view my practice hours per instrument. Only total practice hours can be viewed. It would be beneficial to see my practice hours for specific instruments."

I created this UI and shared with our engineers. Any feedback is welcome!

Merged "Practice hour by instruments or by skills" #594

Merged "Add more stats info" #803