New project workflow

When a user starts a new project, they should be able to select:

1. State
2. What type of districts (house, state senate, state house, other; these will pre-populate number of districts and ideal population for each district)
3. Number if districts & ideal population override (ability to change the default)

No files, tests, or entry points are named. Start by locating the existing new-project workflow in the frontend and review how project state and district settings are represented; the work is done when users can select a state and district type, see the corresponding defaults, and override the district count and ideal population.

Written by the indexing model from the issue text.