static checkIfSymlinksNeedToBeEnabled(ui) {
    return this._setup(ui).checkIfSymlinksNeedToBeEnabled();
  }
if not windows, will fulfill with:
 `{ windows: false, elevated: null)`

if windows, and elevated will fulfill with:
 `{ windows: false, elevated: true)`

if windows, and is NOT elevated will fulfill with:
 `{ windows: false, elevated: false)`

 will include heplful warning, so that users know (if possible) how to
 achieve better windows build performance

@public
@method checkIfSymlinksNeedToBeEnabled
@return {Promise<Object>} Object describing whether we're on windows and if admin rights exist