RFR: 8313424: JavaFX controls in the title bar (Preview) [v84]

[Michael Strauß]

> Implementation of [`StageStyle.EXTENDED`](https://gist.github.com/mstr2/0befc541ee7297b6db2865cc5e4dbd09).

Michael Strauß has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 108 commits:

 - Fix full-screen bug
 - Merge branch 'master' into feature/extended-window
 - only dispose ViewSceneOverlay when non-null
 - Rename default window button style classes
 - Set the scene root as the parent of the overlay node
 - rename WindowManager to DesktopEnvironment
 - enable preview feature system properties for tests
 - javadoc fix
 - fix memory leak in ViewScene
 - Merge branch 'master' into feature/extended-window
 - ... and 98 more: https://git.openjdk.org/jfx/compare/72c1c21a...3fdc465f

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Changes: https://git.openjdk.org/jfx/pull/1605/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1605&range=83
  Stats: 6844 lines in 78 files changed: 6154 ins; 524 del; 166 mod
  Patch: https://git.openjdk.org/jfx/pull/1605.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1605/head:pull/1605

PR: https://git.openjdk.org/jfx/pull/1605