add tools/huawei_files/split_updata.py

The original split_updata.pl seems to be too old, which will not
recognize image names for recent UPDATE.APP .

Usage:
```
  split_updata.py -l UPDATE.APP  # list images in UPDATE.APP
  split_updata.py -u UPDATE.APP  # unpack images to output/
```

Hope python won't bring too many dependencies for Kitchen.