… instead of 1000, consolidate repeated code in aop_download.py and metadata_helpers.py

I've been optimising a lot of Python code recently and offer this as a potential alternative to convert_byte_size().  Removing the nested if.. elif... statements and making it easier to add additional si prefixes in the future if desired.

… instead of 1000, consolidate repeated code in aop_download.py and metadata_helpers.py

…s-python into bh_pos

pulling latest from upstream, was not up to date with main branch

…only tests convert_byte_size

…ch matches the data portal

flake8 config file set to ignore long lines, line break before/after binary operators, and import warnings in init files