Workflows: set timeouts for workflows steps

[bartgol]

I've seen eamxx-sa getting stuck b/c the checkout action got stuck. I killed the workflow after >2h. This was likely due to a loss of network that tripped the container where the action was running, so it shouldn't be too bad. A re-run should have the test going.

However, it's a bit annoying to find out we wasted 2.5h. Luckily, gh actions support both a job-level as well as a step-level timeout via the timeout-minutes entry. We should carefully set this, so that glitches in the container don't cause the job to hang too long. E.g., we could set a 10min timeout for the checkout, a 1h timeout for test-all-scream, and 45min timeout for create_test.

[bartgol]

@E3SM-Project/ci-and-testing I was hoping we could assign an issue to a team (much like one can do for PRs), but apparently it's not possible. 👎