hints on das query to warn user about:

hints warn the user about:
* list case-insensitive matches in DAS cache (DBS3 is case sensistive)
* list dbs instances where the dataset pattern matches with example datasets
hints in config

* make cheetahs '#include' to work
* cleanup how hints are rendered: new template
* new option in config: web_plugins.show_hints
integration between hints, wildcard suggestions and adjust_input

* show hints on case insensitive dataset matches on top (shown only if current case sensitive pattern matches nothing)
* in adjust input, if keyword matches some datasets in current instance, transform into dataset query straight away
* show hints in wildcard suggestions page (no matches)
a more clean workaround for #include
fixes

* use verbose param
* revert the include workaround to set templatedir
* use os.path.join instead of string contactenation in web/tools
refactor hints to use cheetah template
Merge pull request #4154 from dmwm/hints

Hints