Rework graves generation on death

[NightKosh]

Graves generation logic should be splitted on 2 parts:

1. "death event" to get information about player and his death
2. "item drop event" to get items

As I guess such changes should allow collect any items from other mods slots, which should make some compatibility modules useless , and furthermore should allow to close some issues.

TODO:

• Split players graves generation logic
• Create an items backup + console command to get them back(in case of any problems) Backup items at death + command to get them back #280
• Store grave coordinates + console command to show it Player Death coordinates command. #194
• Do something on death in the void Death at falling into the void #281
• Do something with grave generation inside some blocks blocks Mod can't place grave on some places (e.g. torchs), causing itens losses #256
• Allows to change grave generation location for other mods

Check are next sissues fixed or not:

• [1.12] Client Crash on Death (compatibility with Backpack) #274
• Baubles don't stick and are instead destroyed #270
• cofhcore soulbound #269
• Request compatibility for TechGun inventory #257
• Gravestone Camping mod #252
• Minestuck inventory #250