Deprecate duplicated gliding boost method

[imDaniX]

Is your feature request related to a problem?

Currently there's two almost identical methods for giving player a boost while gliding: Spigot's HumanEntity#fireworkBoost(ItemStack) Paper's Player#boostElytra(ItemStack)

Describe the solution you'd like.

Deprecate one of those in favor of other.

Describe alternatives you've considered.

Well, I can just ignore one of those I guess.

Other

No response