Cleanup: Remove searchKeywords from optionspage widgets

If no specialization is provided then the UI strings are searched.

So get rid of extra code collecting all those strings in a lot of
places.

Change-Id: Ibcb48a67e5c7b74e5960fe38b1cb2f74259b503a
Reviewed-by: Eike Ziller <eike.ziller@digia.com>