Add Open Graph meta tags and improve 'description' meta tag

[louiscarnell]

There aren't any Open Graph meta tags or a good description of the site within the <meta name="description"/> tag. This makes the site look a bit plain when sharing online or when it's listed in search results (as can be seen with the preview below from https://metatags.io/).

I would like to work on this (to learn / practice contributing to GitHub).

[jrobind]

Hi @louiscarnell thanks for opening this issue. Feel free to work on this 😄