Add configuration for sharing emoji packs

CHANGELOG.md

README.md

build/webpack.dev.conf.js

src/api/emoji_packs.js

src/lang/en.js

src/router/index.js

src/store/index.js

src/store/modules/emoji_packs.js

src/utils/request.js

src/views/emoji-packs/components/EmojiPack.vue

src/views/emoji-packs/components/NewEmojiUploader.vue

src/views/emoji-packs/components/PropertyEditingRow.vue

src/views/emoji-packs/components/SingleEmojiEditor.vue

src/views/emoji-packs/index.vue