RFR: JMC-7455: Add plugin with support for Jolokia connections

[Martin Skarsaune]

Replaces parts of https://github.com/openjdk/jmc/pull/332

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Commit messages:
 - JMC-7455: Add plugin with support for Jolokia connections

Changes: https://git.openjdk.org/jmc/pull/548/files
 Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=548&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-7455
  Stats: 1624 lines in 34 files changed: 1614 ins; 6 del; 4 mod
  Patch: https://git.openjdk.org/jmc/pull/548.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/548/head:pull/548

PR: https://git.openjdk.org/jmc/pull/548