WEBSITE HOW-TO: Add current incident to Status page

[HenrikBengtsson]

When there's a new active incident on Wynton, we can announce it on the Wynton 'Status' webpage (https://wynton.ucsf.edu/hpc/status/index.html) by:

1. Add the incident to docs/hpc/status/incidents-current.md

2. If severe enough, update "status" banner and green-orange-red indicator by editing docs/_data/status.yml