Increase limitmetrics default to 50.
Increase limitmetrics default to 50.

alexanderzobnin/grafana-zabbix,alexanderzobnin/grafana-zabbix,alexanderzobnin/grafana-zabbix,xiaohuiz/grafana-zabbix,alexanderzobnin/grafana-zabbix,alexanderzobnin/grafana-zabbix,alexanderzobnin/grafana-zabbix,xiaohuiz/grafana-zabbix