refactor: move Vuepress files in dedicated directory

Signed-off-by: Lucien Cartier-Tilet <lucien@phundrak.com>

content/.vuepress/components/ResponsiveImage.vue

@@ -0,0 +1,25 @@
+<template>
+  <img :srcset="srcset" :sizes="sizes" :alt="props.alt" :src="props.src" />
+</template>
+
+<script setup lang="ts">
+const props = defineProps<{
+  src: string;
+  width: number;
+  preview: string;
+  previewWidth: number;
+  previewThreshold?: number;
+  alt?: string;
+}>();
+
+const srcset = [
+  `${props.preview} ${props.previewWidth}w`,
+  `${props.src} ${props.width}w`,
+].join(', ');
+const sizes = [
+  `(max-width: ${props.previewThreshold || props.previewWidth}px) ${
+    props.previewWidth
+  }px`,
+  `${props.width}px`,
+].join(', ');
+</script>