Added project app and basic project model

Added basic fields and initial draft for project model.
There should at least be a test of instantiating a project model in a few configurations (some of the fields might not all be supplied at once, so it would be good to test that we can create objects with different fields being present or not). I bet that the `DecimalField`s might throw errors or something, or maybe some of the fields should be `null=true` or something like that. A test will make sure it works!