Add ability to download a whole channel

[as-muncher]

currently using vividl 0.8

I would love to be able to download an entire youtube channel of videos. Perhaps a setting could be made to download at a certain quality or the next best that will work. Sometimes, you can resolutions that are huge file sizes. So the option to choose max resolution for all videos, maybe some sort of box with checkmarkable options. Best quality audio for all files. I've been finding that if I try to use vividl using the best quality on some videos, that it won't work, but if I choose the same quality but 2 items down the list, then it works.