build: switch from yarn to npm to manage js dependencies and move js contents to root

yarn v1 is being deprecated and starts to have some issues

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

src/views/ErrorView.vue

@@ -0,0 +1,27 @@
+<template>
+  <section class="container mx-auto">
+    <span v-if="code === ErrorCode.REGISTRATION_CLOSED">
+      {{ t("Registration is currently closed.") }}
+    </span>
+
+    <span v-else>
+      {{ t("Unknown error.") }}
+    </span>
+  </section>
+</template>
+
+<script lang="ts" setup>
+import { ErrorCode } from "@/types/enums";
+import { useHead } from "@vueuse/head";
+import { useI18n } from "vue-i18n";
+import { useRouteQuery } from "vue-use-route-query";
+import { computed } from "vue";
+
+const { t } = useI18n({ useScope: "global" });
+
+useHead({
+  title: computed(() => t("Error")),
+});
+
+const code = useRouteQuery("code", null);
+</script>