fix(eslint): Changes eslint existing rules to match the same rules in jitsi meet

.eslintrc.js

         '__filename': false
     },
     'parserOptions': {
+        'ecmaFeatures': {
+            'experimentalObjectRestSpread': true
+        },
         'sourceType': 'module'
     },
     'rules': {
-        'new-cap': [
-            'error',
-            {
-                'capIsNew': false // Behave like JSHint's newcap.
-            }
-        ],
-        // While it is considered a best practice to avoid using methods on
-        // console in JavaScript that is designed to be executed in the browser
-        // and ESLint includes the rule among its set of recommended rules, (1)
-        // the general practice is to strip such calls before pushing to
-        // production and (2) we prefer to utilize console in lib-jitsi-meet
-        // (and jitsi-meet).
-        'no-console': 'off',
-        'semi': 'error'
+        'new-cap': 2,
+        'no-console': 0,
+        'semi': [ 'error', 'always' ]
     }
 };

modules/RTC/ScreenObtainer.js

  */
 var reDetectFirefoxExtension = false;
 
-var GUM = null;
+var gumFunction = null;
 
 /**
  * The error returned by chrome when trying to start inline installation from
     init(options, gum) {
         var obtainDesktopStream = null;
         this.options = options = options || {};
-        GUM = gum;
+        gumFunction = gum;
 
         if (RTCBrowserType.isFirefox())
             initFirefoxExtensionDetection(options);
  * 'about:config'.
  */
 function obtainWebRTCScreen(options, streamCallback, failCallback) {
-    GUM(['screen'], streamCallback, failCallback);
+    gumFunction(['screen'], streamCallback, failCallback);
 }
 
 /**
  */
 function onGetStreamResponse(response, onSuccess, onFailure) {
     if (response.streamId) {
-        GUM(
+        gumFunction(
             ['desktop'],
             stream => onSuccess(stream),
             onFailure,

modules/xmpp/ChatRoom.js

             self.packet2JSON($(this), node.children);
         });
     },
-    JSON2packet: function (nodes, packet) {
+    json2packet: function (nodes, packet) {
         for(let i = 0; i < nodes.length; i++) {
             const node = nodes[i];
             if(!node || node === null){
             if(node.value)
                 packet.t(node.value);
             if(node.children)
-                this.JSON2packet(node.children, packet);
+                this.json2packet(node.children, packet);
             packet.up();
         }
         // packet.up();
             pres.up();
         }
 
-        parser.JSON2packet(this.presMap.nodes, pres);
+        parser.json2packet(this.presMap.nodes, pres);
         this.connection.send(pres);
         if (fromJoin) {
             // XXX We're pressed for time here because we're beginning a complex