RFR: 7455: Add support for jolokia JMX service connection [v6]

[Martin Skarsaune]

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

Martin Skarsaune has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains ten commits:

 - Merge remote-tracking branch 'origin/master' into jolokia-support-only
 - JMC-7455: Provide env map for discovered jolokia connections
 - JMC-7455: Clean up some test comments
 - JMC-7455: Ensure that jolokia version is set
 - JMC-7455: Fix copy paste and outdated errors in Jolokia plugin manifest
 - JMC-7455: Fixed whitespace of feature declaration
 - JMC-7455: Fix copyright notices (change year) in Jolokia plugin
 - JMC-7455: Fix rjmx imports after rebasing with master
 - 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=05
  Stats: 1623 lines in 35 files changed: 1614 ins; 5 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