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>
Ok, it's another possible solution.
But if there are not special contraindications with my solution, I think we can leave it if we have time to rewrite it, instead spend other hours to have the same results.. XD