ui: add discussion reaction (#369)

Co-authored-by: undefined <i@undefined.moe>

packages/ui-default/components/discussion/comments.page.styl

@@ -27,31 +27,6 @@ $downvote-color = red
 
   &:first-child
     border-top: 0
-  
-  .reactions
-    .reaction
-      white-space: nowrap
-      width: auto
-      border-radius: 1.75rem
-      overflow: visible
-      font-size: rem($font-size-small)
-      display: inline-block
-      line-height: rem(22px)
-      padding: rem(0 10px)
-      vertical-align: middle
-      border-radius: rem(12px)
-      border: 1px solid $supplementary-border-color
-      cursor: pointer
-      &.active, &:hover
-        text-decoration: none
-        border-color: $primary-color
-        color: #FFF !important
-      &.active
-        background-color: lighten($primary-color, 10%) !important
-      &:hover
-        background-color: lighten($primary-color, 30%) !important
-      .emoji
-        margin-right: rem(5px)
 
 .dczcomments__reply
   >.media