Create AttributeConfiguration starting with project object

# 🙋 feature request

I like that AttributeConfiguration.new()... allows me to create an attribute without knowing the underlying JSON. But the only way to use it now is to first use "from tamr_unify_client.project.attribute_configuration.resource import AttributeConfiguration", an approach that I've seen can be unstable.

## 🤔 Expected Behavior

my_project.attribute_cofigurations().new().with_attribute_name("foo").with_similarity_function("GEOSPATIAL_HAUSDORFF")...etc...etc

## 😯 Current Behavior

I need to import the AttributeConfiguration class, ...new().with_(...)put()

## 🔦 Context

I want to provide a script to a customer that (a) doesn't include JSON and (b) is robust to changes in the project-structure of the python client.