Utility method for getting unprivileged home directory

[aral]

From: lib/Util.js:

static unprivilegedHomeDirectory () {
  if (process.platform === 'win32') {
    return os.homedir()
  } else {
    // Linuxesque: return non-root home folder even if invoked via sudo.
    const accountsFolder = os.platform() === 'darwin' ? 'Users' : 'home'
    return `/${accountsFolder}/${Util.unprivilegedAccountName()}`
  }
}