Dropped the convertFloat64 for white_temperature and brightness. The
code is cleaner.

Cbor return an interface{} for everything, casting to uint64 or float64
is wrong due to the fact that xAAL schemas support both (even int is
possible). So recast everything to float64 and deal w/ that.

float64 mainly because colorful use float64 for everything, so as
brightness is Z in yxz format...

xy decoding is a pain to decode. Thanks to chatgpt, I was able to port
the JS code. The code seems to works fine now.

I need to fix a issue in the xAAL core due to compare of list..