Allow automatically setting Slack status when user is on-call per-schedule

[Nubly]

What would you like to see!

I'm in multiple on-call schedules. Whenever I'm on-call for a specific schedule, I'll set my status within Slack to reflect that of the type of schedule I am on-call for, and some others within my Slack workspace will look for when I have that status to know if they can reach out to me.

It would be nice if, through the Slack integration, Grafana could set my Slack status automatically when my shift starts with a configurable message/emoji.

I realize that sometimes (particularly in poorly managed organizations) people will be on-call for multiple schedules at once. I'm unsure as to how to handle this, would love to hear ideas. Seems like it would be best to just let the later schedule override previous ones.

Product Area

Chatops

Anything else to add?

No response

[github-actions]

The current version of Grafana OnCall, at the time this issue was opened, is v1.13.6. If your issue pertains to an older version of Grafana OnCall, please be sure to list it in the PR description. Thank you 😄!