RFR: 8328746: Remove unused imports in demo apps

[Andy Goryachev]

Using Eclipse IDE to remove unused imports in **demo apps** (3D, Ensemble, etc.) and update the copyright year to 2024. Using wildcard for more than 10 static imports.


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This is a trivial change (though fairly large), 1 reviewer is probably enough.

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Commit messages:
 - 8328746: Remove unused imports in demo apps

Changes: https://git.openjdk.org/jfx/pull/1420/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1420&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328746
  Stats: 399 lines in 75 files changed: 98 ins; 189 del; 112 mod
  Patch: https://git.openjdk.org/jfx/pull/1420.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1420/head:pull/1420

PR: https://git.openjdk.org/jfx/pull/1420