wip commit, add basic popover for emoji reaction select

src/components/react_button/react_button.vue

@@ -0,0 +1,78 @@
+<template>
+  <v-popover
+    :popper-options="popperOptions"
+    :open="showTooltip"
+    trigger="manual"
+    placement="top"
+    class="react-button-popover"
+    @close-group="closeReactionSelect"
+  >
+    <div slot="popover">
+      <div class="reaction-picker">
+        <span
+          v-for="(emoji, key) in emojis"
+          :key="key"
+          class="emoji-reaction-button"
+        >
+          {{ emoji.replacement }}
+        </span>
+        <div class="reaction-bottom-fader" />
+      </div>
+    </div>
+    <div @click.prevent="openReactionSelect" v-if="loggedIn">
+      <i
+        :class="classes"
+        class="button-icon favorite-button fav-active"
+        :title="$t('tool_tip.add_reaction')"
+      />
+      <span v-if="!mergedConfig.hidePostStats && status.fave_num > 0">{{ status.fave_num }}</span>
+    </div>
+  </v-popover>
+</template>
+
+<script src="./react_button.js" ></script>
+
+<style lang="scss">
+@import '../../_variables.scss';
+
+.reaction-picker {
+  width: 10em;
+  height: 8em;
+  font-size: 1.5em;
+  overflow-y: scroll;
+  display: flex;
+  flex-wrap: wrap;
+  padding: 0.5em;
+  text-align:center;
+
+  mask: linear-gradient(to top, white 0, transparent 100%) bottom no-repeat,
+    linear-gradient(to bottom, white 0, transparent 100%) top no-repeat,
+    linear-gradient(to top, white, white);
+  transition: mask-size 150ms;
+  mask-size: 100% 20px, 100% 20px, auto;
+  // Autoprefixed seem to ignore this one, and also syntax is different
+  -webkit-mask-composite: xor;
+  mask-composite: exclude;
+}
+
+.emoji-reaction-button {
+  flex-basis: 20%;
+  line-height: 1.5em;
+  align-content: center;
+}
+
+.fav-active {
+  cursor: pointer;
+  animation-duration: 0.6s;
+
+  &:hover {
+    color: $fallback--cOrange;
+    color: var(--cOrange, $fallback--cOrange);
+  }
+}
+
+.favorite-button.icon-star {
+  color: $fallback--cOrange;
+  color: var(--cOrange, $fallback--cOrange);
+}
+</style>