Refactor video views

Introduce viewers attribute for live videos
Count views for live videos
Reduce delay to see the viewer update for lives
Add ability to configure video views buffer interval and view ip
expiration

server.ts

@@ -117,6 +117,7 @@ import { VideosRedundancyScheduler } from './server/lib/schedulers/videos-redund
 import { RemoveOldHistoryScheduler } from './server/lib/schedulers/remove-old-history-scheduler'
 import { AutoFollowIndexInstances } from './server/lib/schedulers/auto-follow-index-instances'
 import { RemoveDanglingResumableUploadsScheduler } from './server/lib/schedulers/remove-dangling-resumable-uploads-scheduler'
+import { VideoViewsBufferScheduler } from './server/lib/schedulers/video-views-buffer-scheduler'
 import { isHTTPSignatureDigestValid } from './server/helpers/peertube-crypto'
 import { PeerTubeSocket } from './server/lib/peertube-socket'
 import { updateStreamingPlaylistsInfohashesIfNeeded } from './server/lib/hls'
@@ -128,6 +129,7 @@ import { LiveManager } from './server/lib/live'
 import { HttpStatusCode } from './shared/models/http/http-error-codes'
 import { VideosTorrentCache } from '@server/lib/files-cache/videos-torrent-cache'
 import { ServerConfigManager } from '@server/lib/server-config-manager'
+import { VideoViews } from '@server/lib/video-views'
 
 // ----------- Command line -----------
 
@@ -296,11 +298,11 @@ async function startApplication () {
   PeerTubeVersionCheckScheduler.Instance.enable()
   AutoFollowIndexInstances.Instance.enable()
   RemoveDanglingResumableUploadsScheduler.Instance.enable()
+  VideoViewsBufferScheduler.Instance.enable()
 
-  // Redis initialization
   Redis.Instance.init()
-
   PeerTubeSocket.Instance.init(server)
+  VideoViews.Instance.init()
 
   updateStreamingPlaylistsInfohashesIfNeeded()
     .catch(err => logger.error('Cannot update streaming playlist infohashes.', { err }))