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ARROW-7808: [Java][Dataset] Implement Dataset Java API by JNI to C++

Add following Datasets APIs to Java:

- DatasetFactory
- Dataset
- Scanner
- ScanTask
- ScanTask.BatchIterator

Add a native dataset path to bridge c++ Datasets components to Java:

- NativeDatasetFactory (c++ class : DatasetFactory)
- NativeDataset (c++ class: Dataset)
- NativeScanner (c++ class: DisposableScannerAdaptor)

Following c++ components are not JNI-mapped to keep the initial implementation simple:

- Fragment
- ScanTask
- (arrow::)RecordBatchIterator

Add following API to `FileSystemDatasetFactory` to avoid passing file system objects via JNI bridge:

- `FileSystemDatasetFactory::Make( std::string uri, std::shared_ptr<FileFormat> format, FileSystemFactoryOptions options)`

Unit tests are based on `FileSystemDatasetFactory`.

Closes #7030 from zhztheplayer/ARROW-7808

Authored-by: Hongze Zhang <hongze.zhang@intel.com>
Signed-off-by: Micah Kornfield <emkornfield@gmail.com>