Integration with Kepler prometheus exporter from the sustainability project #3117

The Kepler prometheus exporter from the sustainability project seems like a straightforward integration in a number of ways.

1. Would be a traditional Pbench Agent "tool" named kepler which would follow the node_exporter and dcgm patterns
2. Would be to leverage work done for Consider supporting persistent tool data collection from sources not created by a Tool Meister instance #2811 for the kepler exporter(s)