text: Title: Add support for the Active Record Pattern
  Body: ## Problem
  
  <!-- A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] -->
  
  Popular Python ORMs such as the Django ORM have support for the [Active Record Pattern](https://en.wikipedia.org/wiki/Active_record_pattern), e.g.
  
  ```py
  user = User(name='Robert')
  user.save()
  ```
  
  Supporting this pattern could help reduce code duplication and make it easier for users to transition from another ORM to Prisma.
  
  ## Suggested solution
  
  <!-- A clear and concise description of what you want to happen. -->
  
  *API proposal is still a work in progress.*
  
  ```py
  # model objects must still be created using the standard methods
  # this is a separate and more difficult issue due to typing and defaults
  user = await User.prisma().create({'name': 'Robert'})
  
  # TODO: consider renaming record() to object()
  
  # updating a record
  user.name = 'Tegan'
  await user.record().update()
  
  # re-fetching data is in-place
  await user.record().refresh()
  await user.record().refresh(include={'posts': True})
  
  # deleting a record
  await user.record().delete()
  ```
  