Change Password Mechanism

[rstyd]

We need to change the way passwords are handled in Neo4J (if we choose to stick with it). Currently passwords are set in the configuration file and used in start_gdb. I propose we modify this to create an authorization code file when beeflow first starts then the configuration file will have the path to this file.

[aquan9]

I made PR #948 to fix this issue by generating a random base64 value for the password that's stored in the user's home directory config file on generation of the config file.

[pagrubel]

We had to revert the changes from this PR since it caused the issue reported in #959 so I'm re-opening this issue

[rstyd]

Need to additionally make sure we no longer hardcode the neo4j password in the integration test.