CMS-3488 Introduce UI Framework for responsive layout

Fixed SplitPanel and ContentWindow resize in live edit.
Removed @media queries from the less.
Added top level (body) resize listener.
Optimized ContentWizardPanel resize event: add StickyToolbar update.
Fixed WizardStepForm responsive resizing in live panel issue.
Updated outdated styles.
Updated responsive layout.
Added `unAvailableSizeChanged()` call in `onRemoved()`  event handler.
Merge pull request #750 from enonic/CMS-3488

CMS-3488 Introduce UI Framework for responsive layout