RFR: 8313424: JavaFX controls in the title bar [v32]

[Michael Strauß]

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

Michael Strauß has updated the pull request incrementally with two additional commits since the last revision:

 - StyleableBooleanProperty -> BooleanProperty
 - Add HeaderBar.overlappingSystemInset property

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1605/files
  - new: https://git.openjdk.org/jfx/pull/1605/files/743626f2..8649f917

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1605&range=31
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1605&range=30-31

  Stats: 202 lines in 3 files changed: 152 ins; 23 del; 27 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