Move digifeeds functions to module

[niquerio]

Most of the functions for the digifeeds cli were in separate files, with the same name as the cli method. This meant they needed to be referred to be a different name in the cli code, which is confusing.

Now they are in a functions.py file.

The add_to_db function was renamed add_to_digifeeds_set since that's the actual important thing that's being done in that script.

add_to_digifeeds_set, check_zephir, and move_to_pickup all create a new item with the given barcode if one doesn't already exist.