Filter private messages in report log

[anisus]

Issue

When attaching an event log to a report, there should be an option to filter out any private messages not involving the reported character.

See discussion on Wolfery Forum: https://forum.wolfery.com/t/clarify-log-attachments-and-their-contents-for-moderation-reports/2412

Notes

• The option should be a checkbox "Exclude private messages with others"
• The checkbox should be checked by default

[anisus]

Resolved in PR #314