[Kimchi-devel] Support async task query classification

Problems to solve: When we generate the debug reports (or upload/download a storage volume), only the request initiator gets task id, and is able to query task status. We need other users from other browser to have same view as the initiator, which is not possible now. Solution: 1. We add async event information, events will also be classified so that users can subscribe events interest them 2. We enable reverse mapping (task to resource which generate them) query for users. So that user can find tasks related to a collection: GET /tasks?init_collection=debugreports after take a look at current implementation, we can also query taget_uri GET /tasks?target_uri=r(^/debugreports/*) (need to be encoded) Since we currently out of support of async events, we may want to add task query for this purpose. Welcome comments!