feat: multisend contract detection

[banteg]

What I did

instead of hardcoding the addresses of multisend contracts on different networks, one can observe there are ever only two addresses, with pre-signed deployment transactions available for both.

instead, we just check the code of all addresses and use the first one that matches the expected code.

i also switched MultiSend for MultiSendCallOnly contract as it doesn't allow making delegatecalls that can modify the safe storage, potentially bricking it or stealing all funds.

both brownie-safe and safe web ui have switched to MultiSendCallOnly as the default.

we only ever delegatecall to the multisend contract itself, which we know is stateless and has the code we matched against the hardcoded bytecode.

fixes: #51

How I did it

How to verify it

from ape_safe.multisend import MultiSend

txn = MultiSend()
print(txn.contract)  # should detect the contract automatically

Checklist

• Passes all linting checks (pre-commit and CI jobs)
• New test cases have been added and are passing
• Documentation has been updated
• PR title follows Conventional Commit standard (will be automatically included in the changelog)

[fubuloubu]

btw we can probably refactor to using a manifest bundled with the package a la ApeWorX/uniswap-sdk@bd6b26e

[fubuloubu]

Maybe manifests/ instead of data/