Post-milestone action items

[yuanzhou]

• Remove those deprecated neo4j properties
• Code profiling to measure the performance improvement for both individual index and full index
• Can we move away from the [:USES_DATA] workaround and link publication to a large number of datasets as direct ancestors? There can be another profiling work against the improvements and we can find out if this still causes performance problems.
• Any other index procedure steps that we can further improve the efficiency?

In neo4j, 7 fields are deprecated and no longer being used:

"created_by_user_display_name"
"displayname"
"hm_uuid"
"last_modified_useremail"
"local_directory_url_path"
"protocol_file"
"protocol_info"