Prevent duplicate consumer account numbers

[schbetsy]

Internal ticket number: 1003

For a single Metro2 event, files may be provided from multiple sources, which means consumer account numbers may not be unique. This PR attempts to prevent account number collision by adding a 'collection' parameter to the parsing process, which will be prepended to each consumer account number. This means that each source or collection of metro2 files will need to be parsed separately. When the collection parameter is omitted, the parser will behave the same as before.

Changes

• Update parse management command to accept new collection parameter
• Update initiate_parsing methods to accept the collection param and send them along to the parser
• Update the parser to send the collection parameter to the parse_from_segment method on the AccountActivity model, where it gets prepended onto the consumer account number for each record.
• Add tests for the updates to the parser and initiate_parsing.py

Testing

1. python manage.py test

Notes

• I updated the parsing wiki to add a collections section that describes how to use this feature.

Todos

• Add to the parsing documentation to explain how this feature is used.

Checklist

• PR has an informative and human-readable title
• Changes are limited to a single goal (no scope creep)
• Code can be automatically merged (no conflicts)
• Passes all existing automated tests
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future todos are captured in comments
• Project documentation has been updated
• Reviewers requested with the Reviewers tool ➡️

[willbarton]

I think this is a really elegant solution to the possibilities of duplicate unrelated account numbers in a single event, without adding complexity to 🎉.