[horde] VFS support for SSH2

[Arjen de Korte]

I've tried to switch from the 'ftp' to the 'ssh2' backend in Gollem to  
no avail. Reading directories works fine and uploading files too, but  
downloading files doesn't. Only if I disable the 'readStream' in  
gollem/lib/Application.php (line 328) it works. Is this a known problem?

Horde installed through PEAR
PHP 7.4.27
PECL SSH2 1.3.1 extension