Update the handler for uploaded project icon when publishing package

[NingW101]

to complete web-devkits/webinizer-webclient#12
please test with #web-devkits/webinizer-webclient#18

[lingyuncai]

We also need to check the equality of config.img and meta.data.webinizer.img at below to see if we need to convert the newly set img value in config.json back to package.json to make the values synced-up in between.

  // project_config.ts - line 737
  set img(v: IProjectIcon | undefined) {
    Object.assign(this.data, { img: v });
    this.save();
    // check here and set back to package.json if needed.
  }

[lingyuncai]

LGTM, thanks Ning!