feat: Solving day 12

[truggeri]

Summary

The solution for this took a number of iterations, but finally breaks down as follows,

1. Collect all the like crops - that is those that have the same character on the input map
2. Iterate through each point in the crop and assign them into unique plots - those that are contiguous on the map
3. Add all the fences around the point, except one that is shared with another point - this means the fence is not needed
4. Iterate over plots and fence positions used to calculate each plots area and perimeter
5. Use each area and perimeter to determine the total cost.