Added integration tests for signature verification, owner revocation, time travel logic.
Please give another review

Adding here that running our test suite locally breaks; added foundry and its bundled chain tool, Anvil to the dependency list. For anyone that hits the

failures:
    erc1271_verifier::tests::test_coinbase_smart_wallet

you need to install foundry with:

# get the installer
curl -L https://foundry.paradigm.xyz | bash

# `source` your shell environment. e.g
source ~/.zshenv

# install foundry  <- this will also install anvil as well as some other chain tools.
foundryup 

then run the tests again, and they should pass.

@tuddman Thanks! I wonder can we easily add foundry in the dev/up to automate this? I tried the scripts here but didn't work.