EXTRA_JAVA_OPTS -Xmx settings ie Grafana crashes openhab 2.4

[rlkoshak (Rich Koshak)]

Grafana Image Renderer

We have all had issues with Grafana generating static png charts for some time now. The root cause is PhantomJS. According to the docs on Grafana’s website: PhantomJS is deprecated since Grafana v6.4 and will be removed in a future release. Please migrate to Grafana image renderer plugin or remote rendering service. For at least a year now rendering the images on an RPi has been unavailable as PhantomJS would run amok and consume all the resources until openHAB itself was killed by the kerne…