Allow configuration of internal parameters

[Uxio0]

For example, currently in multiple places we have HTTP connection pool configurations that could be refactored to get the configuration from environment variables

For example, current code from EthereumClient:

class EthereumClient:
    def __init__(
        self,
        ethereum_node_url: URI = URI("http://localhost:8545"),
        provider_timeout: int = 15,
        slow_provider_timeout: int = 60,
        retry_count: int = 1,
        use_caching_middleware: bool = True,
        batch_request_max_size: int = 500,
    ):

to

class EthereumClient:
    def __init__(
        self,
        ethereum_node_url: URI = URI("http://localhost:8545"),
        provider_timeout: int = int(os.environ.get("ETHEREUM_NODE_TIMEOUT", 15)),
        slow_provider_timeout: int = int(os.environ.get("ETHEREUM_NODE_SLOW_TIMEOUT", 60)),
        retry_count: int = int(os.environ.get("ETHEREUM_NODE_RETRY_COUNT", 1)),
        use_caching_middleware: bool = True,
        batch_request_max_size: int = int(os.environ.get("ETHEREUM_NODE_BATCH_REQUEST_SIZE", 500)),
    ):

or define a configuration class like

class EthereumClientConfiguration:

To refactor the environment reading and configuration