Split existing batches according to maxBatchSize configuration in ParSeqRestClient

Currently maxBatchSize does not affect existing batch GET requests. It is only used to limit size of batch requests created as a result of aggregation, see:

parseq/contrib/parseq-batching/src/main/java/com/linkedin/parseq/batching/BatchImpl.java

Line 188 in 1608fb0

    
           if (_batchSize == 0 || (safeToAddWithoutOverflow(_batchSize, size) && _batchSize + size <= _maxSize)) {

This change is to make sure that all outgoing batch GET requests have size below maxBatchSize even if original batch GET request had a larger size.

We have decided to document this in parseq-restli-client README.md for this behavior, this has been committed in master.