refactor: Migrate to Vue components

client/js/components/loading-spinner.vue

@@ -0,0 +1,12 @@
+<template lang="pug">
+  i.nav-item#notifload(v-bind:class='{ "is-active": loading }')
+</template>
+
+<script>
+  import { mapState } from 'vuex'
+
+  export default {
+    name: 'loading-spinner',
+    computed: mapState(['loading'])
+  }
+</script>