Merge BRAN2020_demo tools into ACDtools

[Thomas-Moore-Creative]

# Append the directory of the module to sys.path - import functions
sys.path.append('/g/data/es60/users/thomas_moore/code/Climatology-generator-demo/src/')
import bran2020_demo_functions as my_tools
from bran2020_demo_functions import keep_only_selected_vars, load_rechunker_config, print_chunks, rechunk_each_st_ocean, remove_zarr_encoding, version_table, concatinate_st_ocean_zarrs

bring these into ACDtools