RFR: 8290473: update Eclipse .classpath in apps, buildSrc [v6]

[Andy Goryachev]

> The goal of this change is to make sure jfx repo can be imported as a gradle project in eclipse and all nested projects in the workspace compile with no errors.
> 
> - updated .classpath entries in apps/
> - added utf-8 prefs in .settings/

Andy Goryachev 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:

 - 8290473: junit 5
 - Merge remote-tracking branch 'origin/master' into 8290473.apps
 - 8290473: removed eclipse project in buildSrc
 - 8290473: whitespace
 - 8290473: added initDirs task
 - Merge remote-tracking branch 'origin/master' into 8290473.apps
 - 8290473: added ColorCube project
 - 8290473: eclipse config for apps

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/858/files
  - new: https://git.openjdk.org/jfx/pull/858/files/3238b5f0..b63f4d19

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=858&range=05
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=858&range=04-05

  Stats: 440 lines in 4 files changed: 417 ins; 10 del; 13 mod
  Patch: https://git.openjdk.org/jfx/pull/858.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/858/head:pull/858

PR: https://git.openjdk.org/jfx/pull/858