[Sudan] Metrics - Military Coup and internet shutdown

There was an internet shutdown in Sudan this week.

We should add to metrics-timeline repo:

Articles:

• https://qz.com/africa/2079718/sudan-shuts-down-the-internet-after-a-military-coup/
• https://www.accessnow.org/sudan-internet-shutdown-military-coup/

Metrics: https://metrics.torproject.org/userstats-relay-country.html?start=2021-07-31&end=2021-10-29&country=sd&events=off