Support loading devnet state from path

[antazoey]

Overview

Support the --load-path LOAD_PATH flag argument in the starknet-devnet subprocess for local network.

Specification

• The user can save a state file (JSON?) and use the config starknet: local: state: path/to/file and have it always use that state when starting.
• When using the networks context manager, the user can set chain state in the provider_settings kwarg to allow loading the starknet devnet provider from a state.
• When the user calls provider.update_settings() with new state, the process gets restarted with that new state.

Dependencies

Include links to any open issues that must be resolved before this feature can be implemented.