Remove iroha_crypto, iroha_config and iroha_data_model from Cargo.toml

[mversic]

Since we have re-exported these dependencies through iroha_client, if any of the documentation examples uses them like in the following Cargo.toml example:

[dependencies]
iroha_client = { version = "=2.0.0-pre-rc.13", path = "~/Git/iroha/client" }
iroha_data_model = { version = "=2.0.0-pre-rc.13", path = "~/Git/iroha/data_model" }
iroha_crypto = { version = "=2.0.0-pre-rc.13", path = "~/Git/iroha/crypto" }
iroha_config = { version = "=2.0.0-pre-rc.13", path = "~/Git/iroha/config" }

replace it with:

[dependencies]
iroha_client = { version = "=2.0.0-pre-rc.13", path = "~/Git/iroha/client" }

this will also require that we access these dependencies:

use iroha_config::client::Configuration;
use iroha_crypto::KeyPair;
use iroha_data_model::prelude::*;

through iroha_client like this:

use iroha_client::{
    config::Configuration,
    crypto::KeyPair,
    data_model::prelude::*,
};