Enhance DTW to support time series with different lengths

[lizhizhou]

Description

Current DTW UDF only supports time series with the same length. All row with null value is ignored. This is not the common case that DTW will be used. DTW is usually used to check the distance between time series with different lengths. This PR is to enhance DTW to support this case.

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This PR has:

• [ ] been self-reviewed.
  • [ ] concurrent read
  • [ ] concurrent write
  • [ ] concurrent read and write
• [ ] added documentation for new or modified features or behaviors.
• [ ] added Javadocs for most classes and all non-trivial methods.
• [ ] added or updated version, license, or notice information
• [ ] added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• [ ] added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage.
• [ ] added integration tests.
• [ ] been tested in a test IoTDB cluster.

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Key changed/added classes (or packages if there are too many classes) in this PR

[HTHou]

@trin1t PTAL