Placeable Suspicious Blocks

Adds a number of block items representing suspicious sand and gravel blocks with predefined loot tables. Originally, suspicious blocks can't be easily placed artificially so they have items inside.

Also supports items with custom defined Item/LootTable contents, example:

• /give [Player] brushables:custom_suspicious_sand(or gravel){Item:"..."}
  OR
• /give [Player] brushables:custom_suspicious_sand(or gravel){LootTable:"..."}