hook(rpc-server): Proxy *poolv1.near contracts on function_call

[kobayurii]

The temporary solution is to avoid a lot of read queries to the database.

During contract execution, we provide the host function to the contract runner, which fetches the key directly from ScyllaDB. This works great for most contracts that require a few keys during execution.

The problem with this approach shows itself during the Staking Pool contract call of the method get_accounts

pub fn get_accounts(&self, from_index: u64, limit: u64) -> Vec<HumanReadableAccount> {
    let keys = self.accounts.keys_as_vector();

    (from_index..std::cmp::min(from_index + limit, keys.len()))
        .map(|index| self.get_account(keys.get(index).unwrap()))
        .collect()
}