RFR: 8358450: Viewport characteristics media features [v6]

[Michael Strauß]

> Implementation of [viewport characteristics media features](https://www.w3.org/TR/mediaqueries-5/#mf-viewport-characteristics):
> * `width`
> * `height`
> * `aspect-ratio`: width / height
> * `orientation`: `portrait`, `landscape`
> * `display-mode`: `fullscreen`, `standalone` (note: `browser` and `minimal-ui` are not supported in JavaFX)

Michael Strauß has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:

 - Merge branch 'master' into feature/media-features-viewport-characteristics
 - Refactor context awareness
 - Merge branch 'master' into feature/media-features-viewport-characteristics
 - Merge branch 'master' into feature/media-features-viewport-characteristics
 - Clarify and test handling of text case
 - documentation
 - Replace context awareness flags with EnumSet
 - Add viewport characteristics media features

-------------

Changes:
  - all: https://git.openjdk.org/jfx/pull/1844/files
  - new: https://git.openjdk.org/jfx/pull/1844/files/d93fc2d0..1c1c118d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1844&range=05
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1844&range=04-05

  Stats: 330 lines in 185 files changed: 77 ins; 44 del; 209 mod
  Patch: https://git.openjdk.org/jfx/pull/1844.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1844/head:pull/1844

PR: https://git.openjdk.org/jfx/pull/1844