Add remote family sharing options

[Revadike]

There's still some methods missing from the family sharing implementation introduced by https://github.com/DoctorMcKay/node-steam-user/pull/293, like authorizing remote devices. You can find a list of all family sharing methods here

I'll try to look into this myself later, perhaps you'll find a PR from me in the future to resolve this issue. I'll update this issue with my progression or findings.