Change core shutdown sequence

Now the cluster, restreamer (processes), and the servers (HTTP, HTTP, RTMP, SRT)
are shutdown first, then any other services. Before, e.g. the session collector
was closed very early before the servers. This would have lead to loss of a few
sessions.

app/api/api.go

@@ -1734,20 +1734,6 @@ func (a *api) stop() {
 		a.cluster.Shutdown()
 	}
 
-	if a.iam != nil {
-		a.iam.Close()
-	}
-
-	if a.update != nil {
-		a.update.Stop()
-		a.update = nil
-	}
-
-	if a.service != nil {
-		a.service.Stop()
-		a.service = nil
-	}
-
 	// Stop all restream processes
 	if a.restream != nil {
 		logger.Info().Log("Stopping all processes ...")
@@ -1755,38 +1741,6 @@ func (a *api) stop() {
 		a.restream = nil
 	}
 
-	if a.process != nil {
-		a.process.Stop()
-		a.process = nil
-	}
-
-	// Stop the session tracker
-	if a.sessions != nil {
-		a.sessions.UnregisterAll()
-		a.sessions.Close()
-		a.sessions = nil
-	}
-
-	// Unregister all collectors
-	if a.metrics != nil {
-		a.metrics.UnregisterAll()
-		a.metrics = nil
-	}
-
-	if a.prom != nil {
-		a.prom.UnregisterAll()
-		a.prom = nil
-	}
-
-	// Free the cached objects
-	if a.cache != nil {
-		a.cache.Purge()
-		a.cache = nil
-	}
-
-	// Free the S3 mounts
-	a.s3fs = map[string]fs.Filesystem{}
-
 	// Stop the SRT server
 	if a.srtserver != nil {
 		a.log.logger.srt.Info().Log("Stopping ...")
@@ -1835,11 +1789,56 @@ func (a *api) stop() {
 		a.sidecarserver = nil
 	}
 
+	if a.iam != nil {
+		a.iam.Close()
+	}
+
+	if a.update != nil {
+		a.update.Stop()
+		a.update = nil
+	}
+
+	if a.service != nil {
+		a.service.Stop()
+		a.service = nil
+	}
+
+	if a.process != nil {
+		a.process.Stop()
+		a.process = nil
+	}
+
+	// Unregister all collectors
+	if a.metrics != nil {
+		a.metrics.UnregisterAll()
+		a.metrics = nil
+	}
+
+	if a.prom != nil {
+		a.prom.UnregisterAll()
+		a.prom = nil
+	}
+
+	// Free the cached objects
+	if a.cache != nil {
+		a.cache.Purge()
+		a.cache = nil
+	}
+
+	// Free the S3 mounts
+	a.s3fs = map[string]fs.Filesystem{}
+
 	// Stop resource observer
 	if a.resources != nil {
 		a.resources.Stop()
 	}
 
+	// Stop the session tracker
+	if a.sessions != nil {
+		a.sessions.Close()
+		a.sessions = nil
+	}
+
 	// Stop the GC ticker
 	if a.gcTickerStop != nil {
 		a.gcTickerStop()