use single userparameter line for zabbix

zabbix package currently has 190 userparameter entries like these :

UserParameter=MySQL.Sort-scan,/var/lib/zabbix/percona/scripts/get_mysql_stats_wrapper.sh kt
UserParameter=MySQL.slave-stopped,/var/lib/zabbix/percona/scripts/get_mysql_stats_wrapper.sh jh

essentially, they all have different keys, then run the same script with a different parameter. these could be collapsed in a single line like this :

UserParameter=mysql.statistics[*],/var/lib/zabbix/percona/scripts/get_mysql_stats_wrapper.sh "$1"

note the [*] part after the key - it tells zabbix agent to replace dollarsign-number positional references with item key parameters.

with the current implementation, item keys are like this :
MySQL.Sort-scan
MySQL.slave-stopped

with the single entry, the corresponding keys would be :
mysql.statistics[kt]
mysql.statistics[jh]

additional parameters can be passed as $2, $3 etc and then specified in the key (key[param1, param2, param3...], but that does not seem to be necessary at this time.

note that this will require changing all item keys in the template, too