RFR: 7767: Fix handling of version qualifier in core plugins

[Christoph Langer]

This PR adds some maven antrun magic to handle the .qualifier version property in core modules

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Commit messages:
 - JMC-7767

Changes: https://git.openjdk.java.net/jmc/pull/396/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=396&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-7767
  Stats: 59 lines in 1 file changed: 58 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jmc/pull/396.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/396/head:pull/396

PR: https://git.openjdk.java.net/jmc/pull/396