CMS-3332 Site label used in content lists and and dialogues

Replaced font-family definition with less function.
Moved content WizardPanel styles to new the file
`content-wizard-panel.less`
CMS-3332 Site label used in content lists and and dialogues

Fixed check, so the overlay will be displayed on sites only, not every
and each site content.
Merge pull request #701 from enonic/CMS-3332

CMS-3332 Site label used in content lists and and dialogues