[SSF-133] set up MVP of cron job

[amywng]

ℹ️ Issue

Closes #133

📝 Description

• Added donations.scheduler.ts with cron job that runs every day at 9 AM
• The cron job currently just logs in the backend and calls the donation service to log in the console

✔️ Verification

I verified that the cron job was running by setting the cron pattern to be every minute @Cron('* * * * *') and running the backend to see the logs. You could alternatively do every second to verify this quicker (@Cron('* * * * * *'))

🏕️ (Optional) Future Work / Notes

Did you notice anything ugly during the course of this ticket? Any bugs, design challenges, or unexpected behavior? Write it down so we can clean it up in a future ticket!