Add configuration for sharing emoji packs

This adds the configuration interface for the endpoints introduced here.

src/api/emoji_packs.js

@@ -43,7 +43,7 @@ export async function createPack(host, token, name) {
 export async function listPacks(host) {
   return await request({
     baseURL: baseName(host),
-    url: `/api/pleroma/emoji/packs/list`,
+    url: `/api/pleroma/emoji/packs/`,
     method: 'get'
   })
 }