* feat: add config for impersonating accounts to BS

Useful for testing against hardhat forks.

* Make block offset configurable (#865)

* feat: make block offset configurable

* Add a USE_HARDHAT config

* batch-submitter: must pass both impersonate options (#866)
Co-authored-by: Mark Tyneway <mark.tyneway@gmail.com>

* batch-submitter: update example env

* batch-submitter: lint fix

* batch-submitter: clean up old comments

* batch-submitter: USE_HARDHAT

* batch-submitter: add error messages
Co-authored-by: Mark Tyneway <mark.tyneway@gmail.com>