Bits to band

[fitoprincipe]

A simplified version of the old "BitsReader".

The main idea is to be able to decode the bit bands using the same information as provided by GEE in the dataset's description, like the QA_PIXEL bands here. The only work the user needs to do is convert this:

Bit 3: Cloud
Bit 4: Cloud Shadow
Bit 5: Snow
Bit 6: Clear
  0: Cloud or Dilated Cloud bits are set
  1: Cloud and Dilated Cloud bits are not set
Bit 7: Water
Bits 8-9: Cloud Confidence
  0: None
  1: Low
  2: Medium
  3: High
Bits 10-11: Cloud Shadow Confidence
  0: None
  1: Low
  2: Medium
  3: High

to this

{
  "3": "Cloud",
  "4": "Cloud Shadow",
  "5": "Snow",  
  "7": "Water",
  "8-9": {
    "1": "Clouds Low Prob"
    "2": "Clouds Medium Prob"
    "3": "Clouds High Prob"
  },
  "10-11":  {
    "1": "Shadow Low Prob",
    "2": "Shadow Medium Prob",
    "3": "Shadow High Prob"
  }
}

It doesn't need to contain all classes but just the needed ones.