[code-reflection] RFR: OnnxLift prototype [v5]

[Adam Sotona]

> This is a prototype of OnnxLift tool.
> It lifts ONNX model binary to ONNX code reflection model, extracts weights, and generates Java model source.

Adam Sotona has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:

 - fixed imports
   
 - rollback of Tensor factory as Constant attribute
   
 - fixed imports
   
 - Merge branch 'code-reflection' into onnx-lift-prototype
 - added class name cmd option
   
 - refactoring split to JavaTemplate
   
 - missing annotation
   
 - OnnxLift prototype

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Changes:
  - all: https://git.openjdk.org/babylon/pull/638/files
  - new: https://git.openjdk.org/babylon/pull/638/files/bf54e820..943b85af

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=638&range=04
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=638&range=03-04

  Stats: 52309 lines in 88 files changed: 44061 ins; 4353 del; 3895 mod
  Patch: https://git.openjdk.org/babylon/pull/638.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/638/head:pull/638

PR: https://git.openjdk.org/babylon/pull/638