KAFKA 10409: Refactor Kakfa Streams RocksDB Iterators

[fonsdant]

Key refactorings:

• Use RocksDBDualCFRangeIterator for DualColumnFamilyAccessor#all, since it iterate over all when passing null as from and to key ranges;
• Create helper methods to:
  • loadNextKeys();
  • fetchNextKeyValue();
  • handleWithTimestampOnly();
  • handleNoTimestampOnly();
  • compareAndHandleKeys();
  • check if some key-value isInRange(); and
  • ensureOpen().
• Rewrite methods with new helper methods:
  • makeNext();
  • next(); and
  • hasNext().
• Improve members naming with:
  • noTimestampNext;
  • withTimestampNext;
  • noTimestampIterator; and
  • withTimestampIterator.
• Sort members and method arguments alphanumerically;
• Add documentation.