Improve output when running commands across the whole monorepo

[mcmire]

Because yarn workspaces foreach shows output from many commands, if you run e.g. yarn test and there is one package whose tests fails, you have to painstakingly scroll up and rake over the output with a fine-toothed comb. We should make this output easier to read (especially for tests).

[BelfordZ]

test output is very painful, agreed.

[mcmire]

I looked through the Yarn repo to see if anyone has run into this problem and is talking about it, but I didn't find anything. I think we may have to implement this ourselves. Perhaps for all of the scripts we want to run with yarn workspaces foreach, we write the exit code and/or output to a file and then parse that file after the foreach command is done.

[mcmire]

There's also this project which is very cool, although it only works for yarn build. We may find some interesting ideas here though. https://github.com/ojkelly/yarn.build