Description
Currently the Language class falls back to NULL for the domain value of the cookie.
As NULL isn't allowed as parameter in \setcookie() an error occures:

Fatal error: Uncaught TypeError: setcookie() expects parameter 5 to be string, null given in /lib/SimpleSAML/Utils/HTTP.php:1260
Stack trace:
#0/lib/SimpleSAML/Utils/HTTP.php(1260): setcookie('language', 'de', 168234545

Code Version

master

Expected Behavior

Find a simple example of necessary configuration and usage of the library from the project site.

Current Behavior

Find a 1000+ line code written in such a low level th