better help argparse

[initze]

print default values for argparse:

• does not show default values atm

  options:
  -h, --help            show this help message and exit
  --code_dir CODE_DIR   Local code directory
  --raw_data_dir RAW_DATA_DIR
                      Location of raw data
  --processing_dir PROCESSING_DIR
                      Location for data processing
  --inference_dir INFERENCE_DIR
                      Target directory for inference results
  --model_dir MODEL_DIR
                      Target directory for models
  --model MODEL         Model name, examples ['RTS_v6_tcvis', 'RTS_v6_notcvis']
  --use_gpu USE_GPU [USE_GPU ...]
                      List of GPU IDs to use, space separated
  --runs_per_gpu RUNS_PER_GPU
                      Number of runs per GPU
  --max_images MAX_IMAGES
                      Maximum number of images to process (optional)
  --skip_vrt            set to skip DEM vrt creation

https://stackoverflow.com/questions/12151306/argparse-way-to-include-default-values-in-help