feat: support more providers

[adamdecaf]

This is a tracking issue for supporting providers besides PagerDuty. Many of of them integrate with PD so I'm looking to collect feedback on what other providers would be desired.

Possible

• https://healthchecks.io/docs/configuring_checks/ (Cron or Schedule based)
• Squadcast.com
  • Maybe with their delayed notification config https://apidocs.squadcast.com/?version=latest#7742a9af-29fe-4c08-b7c6-40a1f1796e2f

Not Likely

• https://deadmanssnitch.com/docs/api/v1#creating-a-snitch (Scheduling isn't flexible enough)
• https://cronitor.io/docs/monitor-api-v3#user-content-create-monitor (Could update the Cron schedules, but docs are hard to read)
  • Go SDK is hidden in the terraform provider
• checklyhq
  • seems to only allow checks every N minutes - https://developers.checklyhq.com/reference/postv1checksheartbeat

[adamdecaf]

"Messaging apps that support delayed sends"

https://news.ycombinator.com/item?id=41810461

[adamdecaf]

https://docs.allquiet.app/advanced/maintenance

Looks like we could use Muted Mode to snooze incidents.