TE20 training calculator

[Arphaxad]

NEW UPDATE
- Added three macros.
- Clear button: clears all data in the sheet.
- Copy button: copies the sheet allowing you to work with multiple training sessions simultaniously.
- Save button: saves your training session into a new sheet named after the player.

Thank you @Kwal for some of the inspiration to add macros.

I think the next logical step is to build a helper that suggests drill order depending on the skills you want to improve, drill average quality and share of white skills. I haven't given it much thought yet though. Maybe for the future, as such a mechanism would require some work.