Revert "use YAML for installer auth like we do for Koha itself"
[koha_gimpoz] / installer /
drwxr-xr-x   ..
-rw-r--r-- 14949 InstallAuth.pm
drwxr-xr-x - data
-rwxr-xr-x 1062 externalmodules.pl
-rwxr-xr-x 28253 install.pl