Add lamp technology type to metrics (led / halogen / ...)

Backfills type for L0001-L0011 (led) and L0012 (halogen); new
measurements record it via lamp_station.py.

lamps/L0001/metrics.json

@@ -1,6 +1,7 @@
 {
   "name": "L0001",
   "ean": "8718696822708",
+  "type": "led",
   "manufacturer": "Philips",
   "model": "LEDBulb 8W E27 3000K (68W equivalent, 770 lm)",
   "notes": "",