base: move of remote autocomplete field

* Moves the script for autocompletion from groups module to
  base module.

* Refactoring the script as a RequireJS module that returns
  a FlightJS component.

* Adds documentation on how to use it.

Signed-off-by: Leonardo Rossi <leonardo.r@cern.ch>
We are modifying the element in the DOM which is added through WTF and might have an issue in the future. IMHO It might be better if we leave typeahead's API to deal with the element that's all :/