Move unused imagens from public to private

private/images/fontello.svg

private/images/icon-dark.ai

private/images/icon.ai

private/images/icon.hqx

private/images/icon.icns

private/images/icon.ico

private/images/icon3.ai

private/images/loading.psd

private/images/logo.pdf

private/images/options.ai

private/images/rocketbot.ai

private/images/rocketchat.gif

private/images/screen.jpg

public/images/logo/icon_stars_blur.png

public/images/pixel.png

public/images/transparent-pixel.gif