preserve query params in KWS,wildcard suggestions,hints; minor bugfix in urlutils

**this is a non urgent bug fix**, which adds a helper allowing to easily preserve the common params (e.g. instance, limit, view) between the requests (links).

* add a helper function to build links which would preserve the current url parameters (e.g. view, instance, input, limit)
* preserve the selected parameters in:
  - wildcard suggestion links
  - keyword search query result links
  - hint links
* cleanup how hints plugin is added
  - now there's no need to pass the user input arguments, they are taken from request
* off main topic, fix a little bug: accessing undefined variable in urlutils see https://github.com/dmwm/DAS/compare/preserve_url_params?expand=1#diff-0bef3e702565b82309f127d5c9b6f5faR99