Move user directory outside root folder

Okey in this case

'asset' => [
                'type' => 'Stream',
                'prefixes' => [
                    '' => ['../assets'],
                ]
            ],

Url will be https://domain.com/../assets/ and thats something I don’t want.

In this case

'sharedassets' => [
                'type' => 'Stream',
                'paths' => [
                    '/home/grav/www/assets'
                ]
            ],

Plus with this

'asset' => [ 
                'type' => 'Stream',
                'prefixes' => [
                    '' => ['sharedassets://'],
                ]
            ],

It will end up with Absolute stream path with relative lookup not allowed.
So… yeah somehow there must be way to use absolute path and in the same way keep correct url without that …/…/assets or so