RFR: 1036: Extend bot config files to support comments

[Erik Helin]

Hi all,

please review this patch that extends the `JSON` parser to optionally allow both comments and trailing commas (i.e. [JWCC](https://nigeltao.github.io/blog/2021/json-with-commas-comments.html)). I also modified the bot launcher to now use JWCC for its configuration files instead of plain JSON (to allow comments and trailing commas). Note that no other code is updated to use JWCC, so all networking code etc. will still use regular old JSON.

I also added a bunch of tests for the new JWCC "mode".

Thanks,
Erik

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Commit messages:
 - skara-1036

Changes: https://git.openjdk.java.net/skara/pull/1159/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1159&range=00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-1036
  Stats: 343 lines in 4 files changed: 337 ins; 0 del; 6 mod
  Patch: https://git.openjdk.java.net/skara/pull/1159.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1159/head:pull/1159

PR: https://git.openjdk.java.net/skara/pull/1159