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>
hmm instead of passing the value to the virtual input, we could add the value to the original (hidden by typeahead) field. What do you think?