feat: remove unused PreviewImage component

This commit removes the PreviewImage component that hasn't been used for quite some time in the
codebase.

BREAKING CHANGE: deletion of PreviewImage component

content/.vuepress/components/PreviewImage.vue

@@ -1,51 +0,0 @@
-<template>
-  <a class="no-decoration" :href="src">
-    <figure class="img-prev" :style="style">
-      <ResponsiveImage
-        :source="props.src"
-        :size="props.width"
-        :preview="props.preview"
-        :previewWidth="props.previewWidth"
-        :previewTheshold="props.maxwidth"
-      />
-      <figcaption>
-        <slot />
-      </figcaption>
-    </figure>
-  </a>
-</template>
-
-<script setup lang="ts">
-const props = defineProps<{
-  src: string;
-  width: number;
-  preview: string;
-  previewWidth: number;
-  maxwidth?: number;
-}>();
-
-const style = props.maxwidth ? `max-width: ${props.maxwidth}px` : '';
-</script>
-
-<style scoped lang="scss">
-img {
-  height: auto;
-  width: 100%;
-}
-
-figure {
-  float: left;
-  margin: 0.5rem 1rem;
-  display: flex;
-  justify-content: center;
-  align-items: center;
-  flex-direction: column;
-  max-width: 400px;
-}
-
-@media only screen and (max-width: 800px) {
-  figure {
-    float: none;
-  }
-}
-</style>