[code-reflection] Integrated: Hat fixes to support chess

[Gary Frost]

Mainly some doc updates and the changes to support JVML demos. 

We added the start of the HAT chess engine here.  It is not ready to be pulled into this tree yet.

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Commit messages:
 - Doc changes and infra to support JVMLS demos and chess
 - Doc changes and infra to support JVMLS demos and chess

Changes: https://git.openjdk.org/babylon/pull/231/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=231&range=00
  Stats: 294 lines in 9 files changed: 27 ins; 248 del; 19 mod
  Patch: https://git.openjdk.org/babylon/pull/231.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/231/head:pull/231

PR: https://git.openjdk.org/babylon/pull/231