Stream fetching status to socket clients.
Refactor client-side socket code.
Merge branch 'develop' of github.com:TID-Lab/aggie into 1159_fetching_status
Merge branch '1159_fetching_status' into develop
Merge branch 'develop' of github.com:TID-Lab/aggie into 1127_pull_bot
Merge branch '1127_pull_bot' into develop
Merge branch 'develop' of github.com:TID-Lab/aggie into 1010_rss_content_service