fix: add a timeout to abort hanging requests

[crccheck]

For many reasons, http requests may hang. I'll just defer to the official docs:

Nearly all production code should use this parameter in nearly all requests. Failure to do so can cause your program to hang indefinitely

https://2.python-requests.org/en/master/user/quickstart/#timeouts

I was finding that DownloaderForReddit would sometimes hang forever. Adding this timeout fixed it and downloads were correctly recognized as failed.