This method takes a list of entities and saves them into the database using a single INSERT.
We already have the code in mod-inventory-storage:
Move the code from mod-inventory-storage to PgUtil to allow re-use by all modules that use RMB without using copy & paste.
Reject the request if the number of records exceeds 1000 to prevent out-of-memory errors. This method loads all records into the memory before sending them to the database, it does not stream.