Difficulty Death Scaler

Fix:

• timer not well displayed
• /difficultydeathscaler set <number of death> does not always the Minecraft difficulty
• difficulty continues to reduce after 0

Perf:

• optimize TimerTask and Timer

Now, you have to use a netherite ingot on the boss to activate the "reduce difficulty mod" (except for the Ender Dragon).

The "reduce difficulty mod" will buff the boss:

• the buffed Wither cannot be blocked in bedrock
• the buffed Warden is faster and cannot be knockbacked
• the buffer Elder Guardian has more health, is faster, is smaller and is stronger

The command /difficultydeathscaler get shows the timer before next reduce.

Add command /difficultydeathscaler

Balance the game and fix a bug !

Balance

• Reduce time to decrease difficulty (24h → 12h)
• Decrease difficulty when a boss (wither, ender dragon, elder guardian, warden) is killed

Fix

• When someone should not die, the mod increases the number of death

Change difficulty after 7 deaths:

• reduce maximal number of hearts before disabling natural regeneration (by @Leo21)
• disable natural regeneration for 20 deaths and more (by @Leo21)

Fix: difficulty not set to Difficulty Death Scaler's default difficulty. (by @anhgelus)

Update yarn mappings and clean the code. (by @Leo21 and @anhgelus)

First release