Enable removing properties during staging

[robyngit]

During the staging process, we add properties to the vector files (area, centroid, id, etc.), but we also need to ability to remove properties. This came up in a conversation about excluding the Type property from the output of the IWP dataset, since confidence in this classification is not reliable yet. We should allow configuration of a list of properties to remove during processing. This could be included in changes made while working on #7