[code-reflection] Integrated: Hat jextracted backend infra

[Gary Frost]

More jextract infra. 

Specifically created wrappers (cuwrap, clwrap and glwrap).  These wrap jextracted CUDA, OpenCL and OpenGL. providing a consistent API across for jextracted backends to build against as well as allowing us to include non hat examples (just using these wrappers)

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Commit messages:
 - Added missing licenses
 - created clwrap,cuwrap,glwrap and wrap (shared) subprojects
 - Initial code (and bld changes) for jextracted backend infra

Changes: https://git.openjdk.org/babylon/pull/314/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=314&range=00
  Stats: 2063 lines in 27 files changed: 2060 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/babylon/pull/314.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/314/head:pull/314

PR: https://git.openjdk.org/babylon/pull/314