feat: add 'system' inside the theme toggle (#766)

* feat: add 'system' inside the theme toggle

* chore: generate hugo_stats.json

* fix: missing css

* chore: reorganize code

* feat: menu

* chore: simplify

* chore: some i18n

* review

* fix: remove replace

i18n/en.yaml

@@ -7,11 +7,12 @@ dark: "Dark"
 editThisPage: "Edit this page on GitHub →"
 lastUpdated: "Last updated on"
 light: "Light"
+next: "Next"
 noResultsFound: "No results found."
 onThisPage: "On this page"
-tags: "Tags"
 poweredBy: "Powered by Hextra"
+previous: "Prev"
 readMore: "Read more →"
 searchPlaceholder: "Search..."
-previous: "Prev"
-next: "Next"
+system: "System"
+tags: "Tags"