Alerting: Persist annotations from multidimensional rules in batches (#56575)

* Reduce piecemeal state fields

* Read data directly off state instead of rule

* Unify state and context into single struct

* Expose contextual information to layer above setNextState

* Work in terms of ContextualState and call historian in batches

* Call annotations service in batches

* Export format state and reason and remove workaround in unrelated test package

* Add new method to annotation service for batch inserting

* Fix loop variable aliasing bug caught by linter, didn't change behavior

* Incl timerange on annotation tests

* Insert one at a time if tags are present

* Point to rule from ContextualState rather than copy fields

* Build annotations and copy data prior to starting goroutine

* Rename to StateTransition

* Use new bulk-insert utility

* Remove rule from StateTransition and pass in directly to historian

* Simplify annotations logic since we have only one rule

* Fix logs and context, nilcheck, simplify method name

* Regenerate mock

pkg/services/annotations/annotationstest/fake.go

@@ -43,6 +43,21 @@ func (repo *fakeAnnotationsRepo) Save(ctx context.Context, item *annotations.Ite
 		item.Id = int64(len(repo.annotations) + 1)
 	}
 	repo.annotations[item.Id] = *item
+
+	return nil
+}
+
+func (repo *fakeAnnotationsRepo) SaveMany(ctx context.Context, items []annotations.Item) error {
+	repo.mtx.Lock()
+	defer repo.mtx.Unlock()
+
+	for _, i := range items {
+		if i.Id == 0 {
+			i.Id = int64(len(repo.annotations) + 1)
+		}
+		repo.annotations[i.Id] = i
+	}
+
 	return nil
 }