migrate LegacyCallout to comps

Author: cwaring

docs/.vuepress/theme/components/LegacyCallout.vue

@@ -0,0 +1,44 @@
+<template>
+  <div class="tip custom-block legacy-callout">
+    <p>
+      This site is in beta.
+      <a
+        href="https://github.com/ipfs/docs/issues/new?assignees=&labels=OKR+3%3A+Content+Improvement%2C+docs-ipfs&template=documentation-issue.md&title=%5BDOCS+ISSUE%5D+Beta+Site+Feedback"
+        target="_blank"
+        >Submit feedback</a
+      >
+      <span v-if="$site.themeConfig.betaTestFormUrl">
+        or
+        <a :href="$site.themeConfig.betaTestFormUrl" target="_blank"
+          >become a tester</a
+        >
+      </span>
+      to help us improve it!
+      <span v-if="legacyUrl" class="content-status-status">
+        <br />
+        <a target="_blank" :href="legacyUrl">View this page on legacy site</a>
+      </span>
+    </p>
+  </div>
+</template>
+
+<script>
+export default {
+  computed: {
+    legacyUrl: function() {
+      return this.$frontmatter && this.$frontmatter.legacyUrl
+    }
+  }
+}
+</script>
+
+<style lang="stylus" scoped>
+.legacy-callout {
+  background-color: #f6f9fa;
+  color: #737681;
+  border-color: #5db5be;
+}
+
+@media (min-width: $MQNarrow) {
+}
+</style>