Nightvision - Add support for helmet integrated devices

[Alien314]

When merged this pull request will:

• Add a secondary check to fnc_onSlotItemChanged and the "unit" playerEventHandler in XEH_postInit for headgear integrated night vision.
• Adds config to remove border from integrated nvg classes and set them to gen 4.
• Adds WP variants of pilot and special purpose helmets that use integrated night vision.

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