[code-reflection] Integrated: Switching to maven build

[Gary Frost]

Switch to maven pretty much complete. 

See hat/README.md

hat/CMakeLists.txt  - left in place in case I missed something.    But it should fail with a 'use maven now message'

Discovered maven profiles. We can use them to only try to build SPRIV if we have beehive.

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Commit messages:
 - Switching to maven build

Changes: https://git.openjdk.org/babylon/pull/143/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=143&range=00
  Stats: 261 lines in 20 files changed: 139 ins; 45 del; 77 mod
  Patch: https://git.openjdk.org/babylon/pull/143.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/143/head:pull/143

PR: https://git.openjdk.org/babylon/pull/143