[Bugfix] Responsive login page
[Bugfix] Responsive login page

Fixed #1195

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