Alerting: Move rule evaluation status logic out of prometheus API and into scheduler (#89141)

* Add health fields to rules and an aggregator method to the scheduler

* Move health, last error, and last eval time in together to minimize state processing

* Wire up a readonly scheduler to prom api

* Extract to exported function

* Use health in api_prometheus and fix up tests

* Rename health struct to status

* Fix tests one more time

* Several new tests

* Handle inactive rules

* Push state mapping into state manager

* rename to StatusReader

* Rectify cyclo complexity rebase

* Convert existing package local status implementation to models one

* fix tests

* undo RuleDefs rename

pkg/services/ngalert/models/alert_rule.go

@@ -886,3 +886,11 @@ func (r *Record) Fingerprint() data.Fingerprint {
 func hasAnyCondition(rule *AlertRuleWithOptionals) bool {
 	return rule.Condition != "" || (rule.Record != nil && rule.Record.From != "")
 }
+
+// RuleStatus contains info about a rule's current evaluation state.
+type RuleStatus struct {
+	Health              string
+	LastError           error
+	EvaluationTimestamp time.Time
+	EvaluationDuration  time.Duration
+}