Split up large developments into phased subdivisions

[pksohn]

As a parcel-level simulation, I want to be able to split up large developments into sub-developments and evaluate the feasibility of these sub-developments on distinct timelines, to more realistically simulate large projects.

This has been requested several times. See Paul's explanation on Discourse:

Unlike the current spot pro forma, iIt will be multi-period in its design, enabling larger projects to be scheduled over multiple periods, and incorporating time-dependent costs and revenue expectations to be reflected in the ROI calculations, which will more appropriately reflect the risk - reward profile of large projects.

[pksohn]

This is really two big stories that we need to get specific about how to handle:

• Phased development - this is the idea that a development project can take longer than one year to complete.
• Split developments - this is the idea that beyond a certain square footage, a parcel is too large to be realistically treated as one potential building, and we should figure out a way to procedurally or manually split the parcel into multiple developable entities.

We have to decide at what "unit of development" these behaviors are handled. Some options off the top of my head:

• Stick with parcels. Split parcels into multiple parcels where need be.
• Replace parcels with something else, like "development sites" as the primary unit of feasibility/development analysis. Parcels can be split into development sites but most parcels are 1:1 with their development site.
• Something else?

This should be split into sub-stories once we have more specificity about what might work best.