feat: worker property on World

[ragoune]

Can set the number of workers for the application. This parameter is important, small simulations work best with smaller workers count

[codecov]

Codecov Report

❌ Patch coverage is 69.23077% with 8 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
world.go	0.00%	8 Missing ⚠️

Files with missing lines	Coverage Δ
collision.go	90.90% <100.00%> (ø)
world.go	4.76% <0.00%> (-0.37%)	⬇️

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