Use `GLPI_ANONTICKET_ICON` and `GLPI_ANONTICKET_NAME`

[antranigv]

While currently we use GLPI_ANONTICKET_LOCALE, we don't actually use GLPI_ANONTICKET_ICON and GLPI_ANONTICKET_NAME.

The application should use these env vars, otherwise it should use some kind of defaults.