Make the demo load data faster and more efficiently using APOC + UNWIND.

Note: if you're using Neo4j 4.0/4.1, set the following config property to speed up bulk loading: dbs.logs.query.enabled=off!

9d54a42 - Refactor to use APOC and UNWIND for batch loading (Dave Voutila)
8226748 - Update to use PaySim 2.3 (Dave Voutila)
0001099 - bump paysim dep to 2.2.0 (Dave Voutila)
e8e2470 - apply google-java-format (Dave Voutila)
e447bf4 - No need to return client id (Dave Voutila)
74cb1e3 - Explicitly consume result of Mule query (Dave Voutila)
41654d7 - Provide details on transaction results (Dave Voutila)
7a49c37 - actually configure logging for once! (Dave Voutila)
4aa776b - Demo code doesn't run if constraints already exist (Dave Voutila)