[Feat][Spark] Neo4j importer

**Is your feature request related to a problem? Please describe.**
Now graphar provides neo4j2graphar example, but doesn't support user defined configuration.

**Describe the solution you'd like**
Provide a user defined json config to import neo4j.

**Additional context**
The json configuration needs to be designed in a user-friendly form.

Start by reviewing the existing neo4j2graphar example and how it currently handles import settings. Design a user-friendly JSON configuration and verify that the importer can use it to support user-defined Neo4j imports.

Written by the indexing model from the issue text.