Multisig account customization (#15)

* Initial changes in multisig_account for timeout

* Revert unintended change

* Add assertion in execute_rejected_transaction and add test cases

* More test case and event emit

* Put parentheses on assert condition

Co-authored-by: sjoshisupra <[email protected]>

* Assert minimal during when updating and emit event with address

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Co-authored-by: sjoshisupra <[email protected]>