[jfx17u] RFR: 8201538: Remove implementation support for applets from JavaFX

[Jose Pereda]

Clean backport of 8201538: Remove implementation support for applets from JavaFX
Reviewed-by: mstrauss, aghaisas, jvos

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Commit messages:
 - 8201538: Remove implementation support for applets from JavaFX

Changes: https://git.openjdk.org/jfx17u/pull/169/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx17u&pr=169&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8201538
  Stats: 3424 lines in 64 files changed: 32 ins; 3308 del; 84 mod
  Patch: https://git.openjdk.org/jfx17u/pull/169.diff
  Fetch: git fetch https://git.openjdk.org/jfx17u.git pull/169/head:pull/169

PR: https://git.openjdk.org/jfx17u/pull/169