`Glow` command rewrite (#2466)
* WIP rewrite, add helper for `glow` and `invisible`
* `perPlayerMap` -> `packetOverrides`
* Prefix isn't required for enum args (`state:`)
* Update meta
* Remove `state:` tab-complete
* `applyByteFlag` -> `applyEntityDataFlag`, imports
* Slight cleanup/opti
* Optimize `setForPlayers` modification checking
* Minor code cleanup
* Use `Predicate` instead of `Function<X, Boolean>`
* Fix `isGlowing` (only need the bukkit method)
* Move `EntityMetadataCommandHelper` to `utilities`
* Move `GlowCommand` to `entity` package + group
* Lowercase `state` argument default value
* Fix `invisible` command syntax meta
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commit: 8976f3f)
