Adding Installation link in footer

Author: erikvansebille

src/data/footer-items.js

@@ -21,6 +21,10 @@ export const footerItems = {
       label: 'Documentation',
       href: 'https://docs.oceanparcels.org/en/latest/index.html',
     },
+    {
+      label: 'Installation',
+      href: 'https://docs.oceanparcels.org/en/latest/installation.html',
+    },
     {
       label: 'Tutorials',
       href: 'https://docs.oceanparcels.org/en/latest/documentation/index.html',