Improve build times

* Fix bulma/buefy being imported many (many !!!) times

* Remove javascript-time-ago because date-fns pretty much does the same
thing

* Make sure languages are loaded asynchronously

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/components/NavBar.vue

@@ -216,8 +216,6 @@ export default class NavBar extends Vue {
 }
 </script>
 <style lang="scss" scoped>
-@import "../variables.scss";
-
 nav {
   .navbar-item {
     a.button {