Make the contracts cache initialization unified. The order of cache
iniitialization is not important and Nottary contract is added to the
bc.contracts.Contracts wrt P2PSigExtensions setting, thus no functional
changes, just refactoring for future applications.
Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
It also brings ToStackItem to Block and Transaction, previously this was
avoided to separate block and transaction packages from VM. But turns out
`transaction` depends on `stackitem` already, so this makes little sense (but
can be shuffled in another way if needed).
Context.Container is still a hash.Hashable because we have a number of
occasions (header or MPT root verification) where there is no ToStackItem
implementation possible. Maybe they can go with `nil` Container, but I don't
want to have this risk for now.
1. `System.Contract.CallNative` expects version on stack.
2. Actual method is determined based on current
instruction pointer.
3. Native hashes don't longer depend on NEF checksum.
But don't change the way we process/store transactions and blocks. Effectively
it's just an interface for smart contracts that replaces old syscalls.
Transaction definition is moved temporarily to runtime package and Block
definition is removed (till we solve #1691 properly).
