inventory service performance

[RichardExley]

I created a util to test the performance of the background processing in the inventory services. Here are the results:

PERF_LOG_STAT: inventory-helidon Processed 1000 orders in 22 seconds
PERF_LOG_STAT: inventory-dotnet Processed 1000 orders in 7 seconds
PERF_LOG_STAT: inventory-go Processed 1000 orders in 7 seconds
PERF_LOG_STAT: inventory-python Processed 1000 orders in 9 seconds
PERF_LOG_STAT: inventory-nodejs Processed 1000 orders in 14 seconds
PERF_LOG_STAT: inventory-helidon-se Processed 1000 orders in 13 seconds
PERF_LOG_STAT: inventory-plsql Processed 1000 orders in 2 seconds