RFR: 8306590: Add Windows/macOS system files to .gitignore

[Andy Goryachev]

Adding the following windows/macos system files to the root .gitignore:

# Ignore macOS files
.DS_Store
.DocumentRevisions-V100 // file backups
.fseventsd/ // contains log of file events 
.Spotlight-V100 // usb root
.Trashes/ // usb root 
.TemporaryItems/ 
.VolumeIcon.icns // attached disk icon
.com.apple.timemachine.donotpresent // time machine

# windows
Desktop.ini // folder view options
Thumbs.db // thumbnail cache

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Commit messages:
 - 8306590: add windows and macos system files to .gitignore

Changes: https://git.openjdk.org/jfx/pull/1116/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1116&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306590
  Stats: 14 lines in 1 file changed: 14 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/1116.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1116/head:pull/1116

PR: https://git.openjdk.org/jfx/pull/1116