Ambari configuration for ranger-tagsync needs to support property for atlas keystore filename

Ranger-Tagsync configuration with Ambari needs to :

1. Provide reasonable defaults for Atlas Endpoint (from Atlas URL) and Atlas-source-download-interval (60000) when Atlasrest is selected as tag-source.

2. Support property ranger.tagsync.source.atlasrest.keystore.filename in the Advanced ranger-tagsync-site tab with default value of /usr/hdp/current/ranger-tagsync/conf/atlasuser.jceks. Without this property, updatetagadminpassword.py script will fail.