add license info

config.toml

@@ -142,6 +142,7 @@ enableGitInfo = true
 
 [params.footer]
     custom = '<a href="/impressum/" target="_blank">Impressum, Haftungsausschluss und Datenschutzerklärung</a>'
+    license = '<a rel="license external nofollow noopener noreferrer" href="https://creativecommons.org/licenses/by-nc/4.0/" target="_blank">CC BY-NC 4.0</a>'
 
 [params.cookieconsent]
     enable = false