Add meta tags for author, and don't allow old author param

layouts/partials/head.html

@@ -32,4 +32,6 @@
     {{ template "_internal/schema.html" . }}
 
     <meta name="description" content="{{ with .Description }}{{ . }}{{ else }}{{if .IsPage}}{{ .Summary }}{{ else }}{{ with .Site.Params.description }}{{ . }}{{ end }}{{ end }}{{ end }}">
+
+    {{ partial "author-metadata.html" . }}
 </head>