[Feature Request]: Support custom certificates for neo4j template

[Polber]

Related Template(s)

Google_Cloud_to_Neo4j

What feature(s) are you requesting?

The original issue is tracked at https://issuetracker.google.com/issues/360030796

"""
Currently customers are facing issues establishing a connection from the Dataflow job to a Neo4j database using TLS encryption with certificate validation ("neo4j+s" connection scheme) while utilizing the "Google_Cloud_to_Neo4j" flex template. The connection was successful when using TLS without certificate validation ("neo4j+scc") while with the connection neo4j+s they are experiencing the error

Caused by: javax.net.ssl.SSLHandshakeException: PKIX path building failed:
  sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

Please advise if there is any way the customers can add "Djavax.net.ssl.trustStore" to JVM when they start a dataflow job without having to build their own custom flex template.
"""