Add new features:
1. plugins of Ambari and k8s deploy
2. specified config 'priority_network' to solve some ip problems
Fix bugs:
fix bugs that rebalance does not work in some case.
fix count(*) from union stmt bug
fix some union stmt bugs
fix bugs when try to schema change a clone replica
* add authentication to DownloadAction
1. use cluster_id as token;
2. add dir limit, only files in data dir can be accessed.
* enable authentication in DownloadAction by default
