Convert mw-ui-formlist to use divs

Forms were enclosed in a ul element. Converting to divs
so we don't have to deal with list styling.

Use mw-ui-vform instead of mw-ui-formlist since it's
no longer a list.

Fixed multi-line checkbox appearance.

Fixed text-underline issue on a.button hover.

Change-Id: I04110566fcca287c30ae591dd37e7e9fe1d1c0d3