Skip metadata and thumbnails if they are past the cutoff date

[geoah]

Hey, I'm playing around with tubesync and I'm trying to add a couple of large channels and bumped into the #260 issue.

Would something like this work? I'm not really familiar with django or the process that media and tasks go through so I might be very off base here. I am also making the assumption that media.skip has already been set on the media entry before we get to the signaling for the thumbnails, which might not be correct.

I'm currently having some issues building the container or even installing deps locally on macos so I haven't tested this; I blame the fact it's pretty late here and will give it another shot tomorrow.

Any issues and ideally suggestions for getting this right would be appreciated!
Regards, George

[meeb]

This is fine for the thumbnail skipping, however I'll revert the changes to signals.py as these break the ability to refresh metadata. This finally makes a some sense to merge, so thanks for the PR even if it took over a year to merge!