task/DES-2614: Track fileObjs when categorizing files

[jarosenb]

Overview:

Currently, categorizing a file in My Projects updates its association IDs but doesn't add relevant metadata like path/filename/length. The V3 transition will be a lot easier if we migrate this data into the entities beforehand. This PR adds hooks to categorization so that fileObjs can be constructed without relying on association IDs.

PR Status:

• Ready.
• Work in Progress.
• Hold.

Related Jira tickets:

• DES-2614

Testing Steps:

1. Categorize/un-categorize files in My Projects and confirm that nothing breaks.