Bulk export (#684)

* First pass (working) collection export to zip

* Add export confirmation screen

* 👕

* Refactor

* Job for team export, move to tmp file, settings UI

* Export all collections job

* 👕

* Add specs

* Clarify UI

app/models/Collection.js

@@ -133,6 +133,11 @@ class Collection extends BaseModel {
     return false;
   };
 
+  @action
+  export = async () => {
+    await client.post('/collections.export', { id: this.id });
+  };
+
   @action
   updateData(data: Object = {}) {
     this.data = data;