Generate OnlineId cross-platform implementation

[Rans4ckeR]

Follow up of:

• .NET 6 Cross platform #341

• Windows specific functionality currently disabled on other platforms:
  • Generate OnlineId (Startup)
    • Registry (Microsoft.Win32)
    • SecurityIdentifier (System.Security.Principal.Windows)
    • WMI (System.Management)

A cross-platform version for Generate OnlineId needs to be implemented.

[SadPencil]

/var/lib/dbus/machine-id and /etc/machine-id (systemd based) on Linux