[pve-devel] Moving to ext js 5, the first steps

[Emmanuel Kasper]

Hello

I have started some preliminary work to upgrade the ext js framework we use in the pvemanager
web ui to version 5.1 This should bring us some slight performance improvements in grid 
rendering, and a more modern themed ui.
Please note that Ext JS 5.1 supports Internet Explorer >= 8.0, so if you're still on
Windows 2000, it is time to upgrade !

Emmanuel