feat(RadioGroup): new component (#730)

Co-authored-by: Benjamin Canac <canacb1@gmail.com>

docs/components/content/examples/RadioGroupExample.vue

@@ -0,0 +1,18 @@
+<script setup>
+const options = [{
+  value: 'email',
+  label: 'Email'
+}, {
+  value: 'sms',
+  label: 'Phone (SMS)'
+}, {
+  value: 'push',
+  label: 'Push notification'
+}]
+
+const selected = ref('sms')
+</script>
+
+<template>
+  <URadioGroup v-model="selected" legend="Choose something" :options="options" />
+</template>