File deletion for reported content

[Hattorius]

CipherDrop is a privacy-first file hosting service, not a platform for illegal or copyrighted content distribution. To ensure compliance, users should be able to report files that may violate copyright or contain illegal content.

To support this functionality, I propose adding a new field called up_for_deletion to the files table. This field will be used to mark files flagged for deletion.

Additionally, the hourly job created in issue #1 should be updated to automatically delete any files where the up_for_deletion field is set to true.

Acceptance Criteria:

• Add up_for_deletion field to the files table, and to the models using the table.
• Modify the existing hourly job to delete all files marked with up_for_deletion = true.