importing projects workflow tech debt

[johrstrom]

While looking at #4178 I think we need to clean this up a bit after we merge.

I'm thinking importing a project should likely route to new_projects_path (i.e, projects_controller#new ) with a POST parameter saying it's an import (like how templates work). This will reduce the amount of routes we have, thereby cleaning it all up a little.

how that'll affect the views, I'm not entirely sure but I feel like importing a project is logically very close to creating a new project (from scratch or from a template).