Add support for custom chain id

[war-in]

Is your feature request related to a problem? Please describe.

starknet.py supports custom starknet instances but doesn't support custom chain id

Describe the solution you'd like

@Arcticae will ask SW about this issue

[Arcticae]

Please consider re-exporting ChainId as Union[StarknetChainId, int (or whichever the types suits the needs here)]

[cptartur]

This might be an easy change, since we're deprecating the chain from Clients anyway (it will only be a part of the signer).

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.