Add removeGameWorld and restoreGameWorld

[TheNormalnij]

Fixes #3607 removeAllGameBuildings cleans only buildings pool and leaves rare dynamic elements in the game world. removeGameWorld fixes that issue by cleaning the dummies pool too.

-- Removes all buildings and dummies from game world and frees both pools
nil removeGameWorld()

-- Restores all buildings and dummies
nil restoreGameWorld()

removeAllGameBuildings and restoreAllGameBuildings will be deprecated and removed in future releases

[Fernando-A-Rocha]

@TheNormalnij will u please update the wiki? Let me know if u need advice

[TheNormalnij]

@TheNormalnij will u please update the wiki? Let me know if u need advice

Yep