RFR: 8345348: CSS media feature queries [v30]

[Michael Strauß]

> Implementation of [CSS media queries](https://gist.github.com/mstr2/cbb93bff03e073ec0c32aac317b22de7).

Michael Strauß has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 46 commits:

 - Merge branch 'master' into feature/media-queries
 - fix wrong <br> HTML tags
 - Merge branch 'master' into feature/media-queries
 - doc
 - reorder Scene.Preferences.colorScheme
 - move doc from Scene.Preferences to Platform.Preferences
 - Merge branch 'master' into feature/media-queries
 - add -fx vendor prefix to prefers-persistent-scrollbars
 - cssref documentation changes
 - added test
 - ... and 36 more: https://git.openjdk.org/jfx/compare/fdd50d86...286e1fd3

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Changes: https://git.openjdk.org/jfx/pull/1655/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1655&range=29
  Stats: 5272 lines in 42 files changed: 4110 ins; 1048 del; 114 mod
  Patch: https://git.openjdk.org/jfx/pull/1655.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1655/head:pull/1655

PR: https://git.openjdk.org/jfx/pull/1655