Fixed validation logic of wizard panes
Fixed validation logic of wizard panes

Validation of the wizard panes is moved to statics, the validation logic
is simplified and no longer requires pane render to detect pane errors

Closes-Bug: 1525950
Change-Id: I598e2551b613442c45c7f1522958703ad8ef193c

eayunstack/fuel-web,eayunstack/fuel-web,huntxu/fuel-web,huntxu/fuel-web,huntxu/fuel-web,huntxu/fuel-web,stackforge/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,stackforge/fuel-web,eayunstack/fuel-web,huntxu/fuel-web,stackforge/fuel-web