[Feat] support splitting single graph into multiple graphs via imagefilters

[fabianbees]

Summary

This change allows the Grafana graph to be split into multiple separate graphs.

This is useful, if multiple values are plotted into the same graph and their value ranges are quite different. So small value changes are much more visible.

Here is an example with and without this change:

Without change

With change

Configuration

The values, which should be separated into an additional graph are specified via the Custom variable grafanaimagefiltersarray.

Each entry inside the grafanaimagefiltersarray defines a new graph and its value specifies which value should be omitted via a var-metricfilter. See the following example:

[martialblog]

Hi, thanks for the PR. I'll have a look at it.

Could you please check the failed phpcs jobs and fix the code style accordingly.

Also this change would require some new documentation in the docs/

[fabianbees]

The code style checks should pass now.

Could you please check the failed phpcs jobs and fix the code style accordingly.

You can also use the following Grafana Dashboard Template see this change in action:
icinga_flux.json