For notary-enabled environment we expect `put` to be signed by alphabet.
Also group notary-disabled logic inside a single if and
add tests for balance checks.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
Create simple running blockchain node with a single validator and
test both contract deployment and method invocations.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
