RFR: 8365: Jolokia - Additional support for security mechanisms related to SSL / authentication, discovery restrictions [v5]

[Martin Skarsaune]

> Note: The majority of the work in this PR is to make it work well with RMI connections. For Jolokia however, it should work out of the box as setting the env var will force https.

Martin Skarsaune has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 10 additional commits since the last revision:

 - Merge remote-tracking branch 'origin/master' into JMC-8365-require-secure-connection
 - JMC-8365: Review fixes: whitespace correction and better naming
 - JMC-8365: Make secure button updating null safe
 - JMC-8365: Fix spots
 - JMC-8365: Make secure button updating null safe
 - JMC-8365: Actually reflect require secure connection back in wizard
 - JMC-8369: revert JmcJolokiaPlugin.java
 - JMC-8365: Remove premature change
 - JMC-8365: Fixed spots
 - JMC-8365: Add option to require secure connection and give hint in error connection if it fails

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Changes:
  - all: https://git.openjdk.org/jmc/pull/665/files
  - new: https://git.openjdk.org/jmc/pull/665/files/af937021..850a233c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmc&pr=665&range=04
 - incr: https://webrevs.openjdk.org/?repo=jmc&pr=665&range=03-04

  Stats: 2183175 lines in 239 files changed: 2181551 ins; 578 del; 1046 mod
  Patch: https://git.openjdk.org/jmc/pull/665.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/665/head:pull/665

PR: https://git.openjdk.org/jmc/pull/665