feat: change labels to meetingLabels for clarity

[bnb]

This changes label to meetingLabel for clarity in the API. For now, I've just effectively changed the name, but if we'd like to add something like additonalMeetingLabels in the future I'd be more than happy to do that work.

[bnb]

Updated to use meetingLabels rather than meetingLabel. I also reverted a handful of changes that I think were likely unnecessary and unclear, which won't show up in the diff now.

I'm also now using npm@7 and it seems that entirely rewrote package-lock.json and updated the version. Trying to get clarity on if that's backwards-compatible or not 😅