erp5_autocompletion_list: Move away generic JS code from RelationField as it should be reusable anywhere.

Limit the number of results to 15 instead of 20 as it seems to be enough (taken from an existing customer project).

RelationField: Implement autocompletion and use it by default once erp5_autocompletion_ui is installed.

erp5_autocompletion_ui: Increase delay before searching from 300ms (default) to 600ms, this should be enough...

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@37468 20353a03-c40f-0410-a6d1-a30d3c3de9de