Adds Firework Trades

• Fletcher (Level 2) - 32x Dura 1 Fireworks for 15 Emeralds.
• Fletcher (Level 3) - 24x Dura 2 Fireworks for 20 Emeralds.
• Fletcher (Level 4) - 16x Dura 3 Fireworks for 25 Emeralds.

Working on Adding a Firework Villager next update

Supports 1.21.5 Planned Backports

• 1.21.4-1.21.0
• 1.20.6-1.20

1.19 and under isnt planned to be supported