Add support for professional favicon

[NGenetzky]

I have done this with my hugo-resume which uses this Theme. It makes it so much more professional looking. Used favicon from favicon.io, such as man-technologist.

Had to add this snippet to "head.html" and then add the relevant files to ./static/.

<link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png">
<link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png">
<link rel="manifest" href="/site.webmanifest">

Also created issue at: https://github.com/aerohub/hugo-orbit-theme/issues/15