Add WKAoI field to Project Model

[rajadain]

Currently we only use WKAoI for new projects. When resuming an old project, we only hydrate the area of interest shape and name from the database, making it impossible to take advantage of the caching functionalities when resuming saved projects. Add a wkaoi field to the Project model and wire it through to the front-end so it is used when resuming saved projects.

[mmcfarland]

To be clear, this will effect existing projects only after this change is made, correct? Old old projects' AoI provenance is lost to history.

[rajadain]

Correct. And all projects will still save the area of interest. When running geoprocessing, we attempt to use the WKAoI if available and valid, otherwise fallback to the area of interest. This is purely an enhancement with no loss of current functionality.