Use indexed keys for energy saving

[mcspr]

• always use indexes with eneTotal
• fix unsigned int comparison with -1
• fix sensorID checks, use magnitude.global index directly as index
• migrate pzemEneTotal to eneTotal
• migrate eneTotal to eneTotal0

[mcspr]

@tonilopezmr and I had also for some reason thought that magnitude.global is the same as _magnitudes index. Instead, it sets itself from _counts[magnitude.type]. All eneTotal indexes are updated from that value now