feat: Add option to link an external registration provider for events

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

js/src/components/Event/ExternalParticipationButton.vue

@@ -0,0 +1,30 @@
+<template>
+  <o-button
+    tag="a"
+    :href="
+      event.externalParticipationUrl
+        ? encodeURI(`${event.externalParticipationUrl}?uuid=${event.uuid}`)
+        : '#'
+    "
+    rel="noopener ugc"
+    target="_blank"
+    :disabled="!event.externalParticipationUrl"
+    icon-right="OpenInNew"
+  >
+    {{ t("Go to booking") }}
+  </o-button>
+</template>
+
+<script lang="ts" setup>
+import { computed } from "vue";
+import { IEvent } from "../../types/event.model";
+import { useI18n } from "vue-i18n";
+
+const { t } = useI18n({ useScope: "global" });
+
+const props = defineProps<{
+  event: IEvent;
+}>();
+
+const event = computed(() => props.event);
+</script>