[FEATURE] new opengraph 'fediverse:creator' meta (#1619)

**Usage**

Site level:

params:
  social:
    fediverse_creator: "@[email protected]"

Page (Overrides Site level value):

---
title: "My Page"
social:
  fediverse_creator: "@[email protected]"
---


Closes #1618 #1642

---------

Co-authored-by: Aditya Telange <[email protected]>

Author: David-Guillot

layouts/partials/templates/opengraph.html

@@ -80,3 +80,7 @@
     {{- end }}
   {{- end }}
 {{- end }}
+
+{{- with (.Param "social.fediverse_creator") }}
+  <meta name="fediverse:creator" content="{{ . }}">
+{{- end }}