This includes caching of the inverter info with a 12h TTL, so the graph
still renders when the inverter has gone to sleep at night.
Signed-off-by: Olivier Mehani <shtrom@ssji.net>
squash! [plugins/solar/fronius] Monitor Solar Inverters using the Fronius Solar API
Use generic caching function to also cache real-time data. This allows
to avoid N/As overnight, which don't aggregate nicely on the yearly
graph.
