Turn off autocompletion for textarea and select elems in the Add Job form

[bogdanghervan]

Firefox pre-fills textarea and select elements with a value previously selected, which can break the form, since some JavaScript interactions are never fired for those values.

Currently, Zend Form's view helpers strip away the autocomplete attribute (Zend Framework 2.3.1).

This has already been fixed (zendframework/zendframework#6739). We should link against the new version when it comes available.