refact: config.classic.php, put common code into a method
refact: config.classic.php, put common code into a method

nboisteault/lizmap-web-client,rldhont/lizmap-web-client,laurentj/lizmap-web-client,rldhont/lizmap-web-client,nboisteault/lizmap-web-client,3liz/lizmap-web-client,laurentj/lizmap-web-client,3liz/lizmap-web-client,nboisteault/lizmap-web-client,laurentj/lizmap-web-client,nboisteault/lizmap-web-client,laurentj/lizmap-web-client,rldhont/lizmap-web-client,3liz/lizmap-web-client,3liz/lizmap-web-client,rldhont/lizmap-web-client