Propose bug triage process + nightly build mgmt process

[jdangerx]

Overview

Sometimes stuff goes wrong! We need to make decisions about how urgently they need to be fixed! If we don't make those decisions, we'll treat everything as urgent and sink hours and hours into stuff that we don't actually care about!

It might be worth writing down some guidelines - but maybe we can just use "discuss as a team how urgent this is" as a process for a little longer. In any case, I tried to sketch out what some written guidelines could look like.

Separately, we have a bit more of an actual process around the nightly build failures now, so I wrote that down.

Testing

Well, other people need to read it and give feedback ;)

# To-do list
- [x] Review the PR yourself and call out any questions or issues you have