[Plank Sack] Fix Mahogany Homes Not Counting Planks

[kramerology]

Fixes #124

Originally, counting planks for Mahogany Homes used the same code as regular construction to extract build costs from the build interface. The recent game update removed this interface for Mahogany Homes so this method was no longer possible.

The plugin already had code to support building a limited number of interface-less items (eg. hat rack) with an assumed cost of 1 plank.

This PR expands that system for all Mahogany Home build hotspots with hardcoded build costs.

Open to suggestions for improvements