Define notification events, implement parsers. Add morph client of
Subnet contract. Listen, verify and approve events in Inner Ring app.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Timer is not suitable for notary deposits because it can never fire
in case of desynchronization or external epoch changes. Notary deposits
must be handled on new epoch event.
Signed-off-by: Alex Vanin <alexey@nspcc.ru>