Converted wikibase.ui.Tooltip to jQuery widget

Removed "old JS UI" components wikibase.ui.Tooltip and wikibase.ui.Tooltip.Extension
replacing it with jQuery.wikibase.wbtooltip widget. Whenever switching to jQuery UI
>= 1.9, there will be no naming conflict with the native tooltip widget added in
jQuery UI 1.9.

Change-Id: Icfe33fc5cf94e1c3e4e92ea0740f509f832cebc9
Merge "Converted wikibase.ui.Tooltip to jQuery widget"