Server.md points to old Passenger install document location

[weex]

This may not be relevant if this isn't the way to install a production server, but wanted to capture that the Passenger installation link in https://github.com/OpenHospitalityNetwork/fedi-trustroots/blob/master/docs/Server.md says the documentation moved.

The new location is https://www.phusionpassenger.com/library/install/nginx/apt_repo/

We can close this if, we don't plan to support this kind of manual installation.

[mariha]

Would be nice to fix it in the upstream repo.