RFR: 8068: Move JMC 9 to JDK 17

[Brice Dutheil]

This PR builds atop #359 which has a number of improvement.
* #359

It removed older platform that didn't support Java17 (see https://wiki.eclipse.org/Eclipse/Installation).

I didn't changed the agent to 17 though.

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Commit messages:
 - Bump core to Java 17
 - Bump application and releng to Java 17
 - Update devguide, import launchers not needed
 - Update devguide
 - Fix agent OSGI entry, was 1.8 but compiled with 11 target
 - Make application pom explicitly targetting Java 11
 - Move OSGI bundles and Eclipse config to JavaSE-11
 - Merge remote-tracking branch 'upstream/master' into bump-to-java11
 - Merge branch 'master' into bump-to-java11
 - Use the release flag to avoid JDK 11 symbols for core libraries (still Java 1.8)
 - ... and 2 more: https://git.openjdk.org/jmc/compare/58c9ede2...d1b6edad

Changes: https://git.openjdk.org/jmc/pull/482/files
 Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=482&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-8068
  Stats: 825 lines in 327 files changed: 4 ins; 406 del; 415 mod
  Patch: https://git.openjdk.org/jmc/pull/482.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/482/head:pull/482

PR: https://git.openjdk.org/jmc/pull/482