initial porting changes

src/_zkapauthorizer/_storage_client.py

src/_zkapauthorizer/_storage_server.py

src/_zkapauthorizer/controller.py

src/_zkapauthorizer/eliot.py

src/_zkapauthorizer/model.py

src/_zkapauthorizer/resource.py

src/_zkapauthorizer/storage_common.py

src/_zkapauthorizer/tests/strategies.py

src/_zkapauthorizer/tests/test_client_resource.py

src/_zkapauthorizer/tests/test_controller.py

src/_zkapauthorizer/tests/test_model.py

src/_zkapauthorizer/tests/test_plugin.py

src/_zkapauthorizer/tests/test_pricecalculator.py