Update docs and examples

JitsiMeetJS.js

      * @param {string} options.resolution resolution constraints
      * @param {string} options.cameraDeviceId
      * @param {string} options.micDeviceId
-     * @param {object} options.desktopSharingExtensionExternalInstallation -
-     * enables external installation process for desktop sharing extension if
-     * the inline installation is not posible. The following properties should
-     * be provided:
      * @param {intiger} interval - the interval (in ms) for
      * checking whether the desktop sharing extension is installed or not
      * @param {Function} checkAgain - returns boolean. While checkAgain()==true

doc/API.md

 *  ```JitsiMeetJS.init(options)``` - this method initialized Jitsi Meet API.
 The ```options``` parameter is JS object with the following properties:
     - `useIPv6` - boolean property
-    - `desktopSharingChromeExtId` - The ID of the jidesha extension for Chrome. Example: 'mbocklcggfhnbahlnepmldehdhpjfcjp'
-    - `desktopSharingChromeDisabled` - Boolean. Whether desktop sharing should be disabled on Chrome. Example: false.
-    - `desktopSharingChromeSources` - Array of strings with the media sources to use when using screen sharing with the Chrome extension. Example: ['screen', 'window']
-    - `desktopSharingChromeMinExtVersion` - Required version of Chrome extension. Example: '0.1'
-    - `desktopSharingFirefoxDisabled` - Boolean. Whether desktop sharing should be disabled on Firefox. Example: false.
     - `disableAudioLevels` - boolean property. Enables/disables audio levels.
     - `disableSimulcast` - boolean property. Enables/disables simulcast.
     - `enableWindowOnErrorHandler` - boolean property (default false). Enables/disables attaching global onerror handler (window.onerror).

doc/example/example.js

 
 // JitsiMeetJS.setLogLevel(JitsiMeetJS.logLevels.ERROR);
 const initOptions = {
-    disableAudioLevels: true,
-
-    // The ID of the jidesha extension for Chrome.
-    desktopSharingChromeExtId: 'mbocklcggfhnbahlnepmldehdhpjfcjp',
-
-    // Whether desktop sharing should be disabled on Chrome.
-    desktopSharingChromeDisabled: false,
-
-    // The media sources to use when using screen sharing with the Chrome
-    // extension.
-    desktopSharingChromeSources: [ 'screen', 'window' ],
-
-    // Required version of Chrome extension
-    desktopSharingChromeMinExtVersion: '0.1',
-
-    // Whether desktop sharing should be disabled on Firefox.
-    desktopSharingFirefoxDisabled: true
+    disableAudioLevels: true
 };
 
 JitsiMeetJS.init(initOptions);

modules/RTC/RTCUtils.js

      * in RTCUtils#_newGetUserMediaWithConstraints.
      *
      * @param {Object} options
-     * @param {Object} options.desktopSharingExtensionExternalInstallation
      * @param {string[]} options.desktopSharingSources
      * @param {Object} options.desktopSharingFrameRate
      * @param {Object} options.desktopSharingFrameRate.min - Minimum fps
      */
     _parseDesktopSharingOptions(options) {
         return {
-            ...options.desktopSharingExtensionExternalInstallation,
             desktopSharingSources: options.desktopSharingSources,
             gumOptions: {
                 frameRate: options.desktopSharingFrameRate
             }
 
             const {
-                desktopSharingExtensionExternalInstallation,
                 desktopSharingSourceDevice,
                 desktopSharingSources,
                 desktopSharingFrameRate
             }
 
             return this._newGetDesktopMedia({
-                desktopSharingExtensionExternalInstallation,
                 desktopSharingSources,
                 desktopSharingFrameRate
             });

modules/RTC/ScreenObtainer.js

 
             window.JitsiMeetScreenObtainer.openDesktopPicker(
                 {
-                    desktopSharingSources: desktopSharingSources
-                        || this.options.desktopSharingChromeSources
+                    desktopSharingSources
                 },
                 (streamId, streamType, screenShareAudio = false) =>
                     onGetStreamResponse(