code: public Instance getLink(final String _key)
          throws EFapsException
      {
          return Instance.get(getValue(_key, ConfType.LINK));
      }
docs: Returns for given <code>_key</code> the related link. If no link is found
  <code>null</code> is returned.
  
  @param _key key of searched link
  @return found link; if not found <code>null</code>
  @throws EFapsException on error
  @see #links