[MM-44488] Cloud limits: enforcing messages (#20362)

* Add new Job to keep updating the last_accessible_post time

* Filter out posts for funcs returning PostList model

* Separate methods to get and compute cache

* filter pinned posts

* For posts with sorted CreateAt order, support a faster form of filtering.

* Add inaccessible header for getPost and getPostsByIDs APIs

* replace manual binary search with the std. library

* in-place filter posts

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
Co-authored-by: Nathaniel Allred <neallred@protonmail.com>

store/timerlayer/timerlayer.go

@@ -5146,6 +5146,22 @@ func (s *TimerLayerPostStore) GetMaxPostSize() int {
 	return result
 }
 
+func (s *TimerLayerPostStore) GetNthRecentPostTime(n int64) (int64, error) {
+	start := time.Now()
+
+	result, err := s.PostStore.GetNthRecentPostTime(n)
+
+	elapsed := float64(time.Since(start)) / float64(time.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if err == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("PostStore.GetNthRecentPostTime", success, elapsed)
+	}
+	return result, err
+}
+
 func (s *TimerLayerPostStore) GetOldest() (*model.Post, error) {
 	start := time.Now()