Updated InfluxDB and Grafana container apps

[mairas]

Many people had problems with InfluxDB and Grafana container apps, because, well, they were broken. 🙈

I've now fixed them. InfluxDB still doesn't authenticate using OIDC, so you need to set the admin password in the container app settings in Cockpit, but Grafana does. And not only that, the connections between signalk-server, InfluxDB and Grafana are configured automagically if any two of those are installed. If you get unexpected results, please let me know.