Upadte ljm (configurable pc stats interval), whitelist config options. (#5106)

config.js

 
     // Disable measuring of audio levels.
     // disableAudioLevels: false,
+    // audioLevelsInterval: 200,
 
     // Enabling this will run the lib-jitsi-meet no audio detection module which
     // will notify the user if the current selected microphone has no audio
     // estimation tests.
     // gatherStats: false,
 
+    // The interval at which PeerConnection.getStats() is called. Defaults to 10000
+    // pcStatsInterval: 10000,
+
     // To enable sending statistics to callstats.io you must provide the
     // Application ID and Secret.
     // callStatsID: '',

package.json

     "js-utils": "github:jitsi/js-utils#8567f86ec2774ae1d1c47b22e3435928cf5d9771",
     "jsrsasign": "8.0.12",
     "jwt-decode": "2.2.0",
-    "lib-jitsi-meet": "github:jitsi/lib-jitsi-meet#47c2bc65457b0cd1620e171cf79ffe4d49d071c5",
+    "lib-jitsi-meet": "github:jitsi/lib-jitsi-meet#b24bbdee4ecd8d42bc047743a5b13f8b14f98b23",
     "libflacjs": "github:mmig/libflac.js#93d37e7f811f01cf7d8b6a603e38bd3c3810907d",
     "lodash": "4.17.13",
     "moment": "2.19.4",

react/features/base/config/configWhitelist.js

     '_peerConnStatusRtcMuteTimeout',
     'abTesting',
     'analytics.disabled',
+    'audioLevelsInterval',
     'autoRecord',
     'autoRecordToken',
     'avgRtpStatsN',
     'nick',
     'openBridgeChannel',
     'p2p',
+    'pcStatsInterval',
     'preferH264',
     'requireDisplayName',
     'resolution',