Adds options to autocomplete module for mapping key/value pairs

The autocomplete module now has `data-module-key` and `data-module-label`
options which map on the JSON response like this. Example JSON AJAX response:

  [
    { "a": 1, "b": 2, "c": 3 },
    { "a": 4, "b": 5, "c": 6 }
  ]

So, let's say the input needs to have `a` as a value but wants to use `c` as
a label within the dropdown.

Therefore: `data-module-key="a" data-module-value="c"`

:boom:
Fixes dataset edit template and adds options for key/value pairs in autocomplete