make Extra Utilities 2 Machine Block drops mutable

[WaitingIdly]

when breaking Extra Utilities 2 Machines, they return an ImmutableList. this causes issues for anything attempting to remove entries from the list, causing an UnsupportedOperationException. in addition to other, unknown things, this impacts the EnderIO Direct upgrade (both upgrade & Tinkers modifier) and the Astral Sorcery Scorching enchantment.

here is the issue reported to EnderIO: SleepyTrousers/EnderIO-1.5-1.12#5360
heres the issue with the Direct upgrade and Astral Sorcery Scorching enchantment (both things modifying the list) being reported elsewhere: Divine-Journey-2/Divine-Journey-2#1138, Divine-Journey-2/Divine-Journey-2#345

[what-the-diff]

PR Summary

• Clarification and update in the documentation
  The README.md file was updated with an explanation about a new feature in the Extra Utilities 2 section. This new feature enables control over what materials are dropped when you dismantle a certain in-game machine, which was earlier fixed and couldn't be altered.

• Introducing toggle to change dropped materials
  In the file UTConfigMods.java, there's a new field, utMutableBlockDrops, added to a class. This new addition allows players to activate or deactivate the feature that allows changing materials dropped from machines.

• Making sure modification works with the game
  In the UTMixinLoader.java file, conditions are put into place to ensure that the modifications to the game will be functional only when Extra Utilities 2 mod is active and if the option to change dropped items is turned on.

• Changing the behavior of the machine dismantling
  A new file UTMutableBlockMachineDrops.java was introduced which changes the function of in-game machines, by granting them the ability to drop different items depending on the settings that the player chose.

• Adding configuration settings for the modification
  A new configuration file mixins.mods.extrautilities.mutabledrops.json was incorporated to allow players to fine-tune the new modification according to their personal preferences.