Add --starknet-network to hardhat test and hardhat run

[FabijanC]

Usage

• Introduces the --starknet-network option to hardhat test and hardhat run commands/tasks.

Dev

• Required some refactoring.
• Introduces new property on the starknet object: networkUrl.
• The feature is also tested, but weakly - it is only asserted (by virtue of receving a status code of zero) that --starknet-network option may indeed be passed.
• Replace any with TaskArguments for args of hardhat tasks.