feat: SLI status panels use confidence for status
This updates the status panels to rely on confidence interval values instead of direct raw value when calculating the status of an SLI.
It also adds the 5m confidence line for SLIs if they're using confidence intervals.
Additionally, some more helpful information about the burn rates is included in the status panel (whether they are degraded, recovering, or deteriorating).
This may help in an incident to understand when things are getting better or worse.
This change also adds some tests for the status panels.
Edited by Andrew Newdigate