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/annotationsimpl/annotations.go

@@ -30,6 +30,12 @@ func (r *RepositoryImpl) Save(ctx context.Context, item *annotations.Item) error
 	return r.store.Add(ctx, item)
 }
 
+// SaveMany inserts multiple annotations at once.
+// It does not return IDs associated with created annotations. If you need this functionality, use the single-item Save instead.
+func (r *RepositoryImpl) SaveMany(ctx context.Context, items []annotations.Item) error {
+	return r.store.AddMany(ctx, items)
+}
+
 func (r *RepositoryImpl) Update(ctx context.Context, item *annotations.Item) error {
 	return r.store.Update(ctx, item)
 }