Release the new Mimir Alertmanager

[Rotfuks]

Motivation

We know how to roll out the Mimir Alertmanager - now we need to announce and do it.

Todo

• Document the change in the architecture in the intranet
• Annonuce the change to the mimir alert manager
  • Check if customers have alerts in place (Dominik can help :))
• Roll out the change

Outcome

We use the mimir alertmanager everywhere.