feat(BACK-8208): tooling: Allow generation from string inputs

[fsamier]

Breaking change

generate.generate_descriptor interface change: method now expects either string or bytes rather than path. Path should be resolved by caller.

generate_descriptor(chain_id=..., contract_address=..., abi_file="/path/to/abi.json")

Should be replaced by:

with open("/path/to/abi.json", "rb") as f:
   generate_descriptor(chain_id=..., contract_address=..., abi=f.read())

CLI is unchanged.