Rename output attachment filenames to follow standard pattern

## What is the problem?
Output attachment file names currently contain mixed case, spaces and don't include a unique identifier.

## What is the impact and proposed solution
As pointed out in recent PR comments, it would be better if our all our output attachment filenames:
- didn't contain spaces (spaces in filenames make for more difficult scripting)
- didn't contain mixed case (different operating systems handle the upper- and lower-case letters differently)
- included a unique_id (since users download the same type of file for multiple clients and using the same filename can cause confusion. Which "incorporation application.pdf" was for ABC Corp?)

Thanks @thorwolpert https://github.com/bcgov/lear/pull/1980#discussion_r1157909599

Start with the linked PR discussion at github.com/bcgov/lear/pull/1980#discussion_r1157909599, then trace where output attachment filenames are produced. Confirm the exact standard pattern and update all affected outputs so names have no spaces or mixed case and include a unique_id; done means every output attachment follows that pattern.

Written by the indexing model from the issue text.