Add XZ compression and streaming support to io

[nmaguiar]

Motivation

• Provide parity with existing gzip helpers by adding support for the XZ compression format using the already-included Apache Commons Compress library.
• Allow scripts and plugins to compress/decompress byte arrays and use streaming XZ readers/writers the same way they do for gzip.

Description

• Added XZ byte-array helpers io.xz(...) and io.unxz(...) implemented with XZCompressorOutputStream / XZCompressorInputStream in src/openaf/core/IO.java.
• Added XZ stream APIs io.writeFileXzStream(...) and io.readFileXzStream(...) in src/openaf/core/IO.java for file streaming support.
• Exposed the new methods through openaf.IOBase (src/openaf/IOBase.java) so they are available via the same public IO surface as existing gzip helpers.
• Added JS tests in tests/autoTestAll.IO.js to validate native byte-array roundtrip (testXzNativeToByte) and stream read/write roundtrip (testIOXzStream).

Testing

• Attempted mvn -DskipTests package; build failed in this environment because the Maven build invokes the ojob tool which is not available here (build step external to code changes).
• Ran a packaging build with exec steps skipped via mvn -DskipTests -Dexec.skip=true package, which completed successfully.
• Added tests in tests/autoTestAll.IO.js (JS oJob tests); they were added to the test suite but were not executed in this environment due to the project build invoking external tooling.