[forms] Add autocomplete attribute for formrenderers If you set form.autocomplete = False, the form renderer in the open form tag will add the html option 'autocomplete=off'. It allows to disable the functionality of some browsers to fill in some forms automatically (for instance a profile with login/password) Closes #3747294

Experiment with the search bar. Try queries like "card sometextualcontent" or
"card wikiid index" or "345".