Assorted fixes

[lucasgelfond]

Docs changes, youtube-dl --> yt-dlp, suggestions for Apple Silicon.

Also generally have meta question about how we want to do PRs here. My instinct is - lots of small changes vs. one big one. Problem is that each individual small change tends to be breaking (even if getting closer to an outcome that works), so possible certain changes break further.

For example, my workflow of using ./mtriage dev and calling python3 src/run.py is failing (I get a 'Illegal instruction' which is a Python error I've never seen before) and the general ./mtriage run docs/tutorial/3/3b.yaml is running (better than I got before!) but seems to just hang on the command (i.e., I'm just stuck here):

Lmk what you prefer! Happy to do whatever but figured good to start the process..

[lucasgelfond]

cc @breezykermo

[lucasgelfond]

Maybe a better way to say this actually is - the src/run.py workflow works as I was using it before (i.e., for 3a in the tutorial), but not for later things we're still working through, like 3b

[lucasgelfond]

This also works now when I try to build a new dev Docker image, once we get some more testing in possible we also want to publish this in place of current image?