Get Started Page is missing copy folder location

[nirvn]

Originally filed by @arc12 at opengisch/QField#4157

This page:
https://docs.qfield.org/get-started/tutorials/get-started-qfs/
does not provide the location to which the package folder should be copied to for Android users.
This would be very helpful for people getting started!
I suggest locations for both "internal" and SD storage should be provided.