refactor code and add collision checks

[brokenmass]

This PR does:

• refactor the code to remove the need of pendingInserters by using native buildpreviews
• add collision checks for pasted inserters
• split the main code into a separate class for readability
• improves performance by removing the need to iterate over all the entities on the planet when looking for the connected assemblers/belt by using native GetBuildingsInAreaNonAlloc method (local search is 40x faster)