unify user popovers into a separate component

src/components/user_popover/user_popover.vue

@@ -0,0 +1,34 @@
+<template>
+<Popover
+  trigger="click"
+  popover-class="popover-default user-popover"
+  overlay-centers-selector=".user-info-avatar-link .Avatar"
+  :overlay-centers="overlayCenters"
+  :disabled="disabled"
+>
+  <template v-slot:trigger>
+    <slot />
+  </template>
+  <template v-slot:content>
+    <UserCard
+      class="user-popover"
+      :user-id="userId"
+      :hide-bio="true"
+      :bordered="false"
+      :allow-zooming-avatar="true"
+      :rounded="true"
+    />
+  </template>
+</Popover>
+</template>
+
+<script src="./user_popover.js" ></script>
+
+<style lang="scss">
+@import '../../_variables.scss';
+
+/* popover styles load on-demand, so we need to override */
+.user-popover.popover {
+}
+
+</style>