Add img/favicon.png

[bact]

• Add favicon.png to img/ folder
  • The image is referred to in the HTML header template code:
    

    codemeta.github.io/themes/hugo-material/layouts/partials/head.html

    Lines 11 to 12 in a802fb8

    	<link rel="apple-touch-icon" sizes="76x76" href="{{ "img/favicon.png" | relURL }}" />
    	<link rel="icon" type="image/png" href="{{ "img/favicon.png" | relURL }}" />

  • The image is taken from https://github.com/codemeta
    
  • It is similar to https://github.com/codemeta/codemeta.github.io/blob/master/static/favicon.ico but bigger (200x200px vs 16x16px).
• Also remove "untitled folder" in img/ (a copy of the img directory itself, likely to be accidentally copied).
  • No code use any of the images inside this directory.