includes the following fixes:
* remove all code related to the old java applet vnc client
(we do not use this anymore)
* move static configuration to class definition
* use Ext.ux.IFrame instead of widget.uxiframe (to be consistent)
* change listener from show to activate (for browser refresh)
* change deprecated autoScroll to scrollable
* remove novnc option from openVNCViewer function,
since we do not need this option anymore
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
ExtJS6 adds accessibility (aria) support to the framework, which means
special handling of space/enter key and panels title, and a lot of
warnings / errors in the browser console
Aria support will be reenabled after all the components are migrated to
ExtJS6
