Proper black-box integration tests MVP

[mversic]

We've long had an issue that our client/tests/integration are not proper black box tests. This means the have iroha as dependency when they shouldn't.

The main goal is to remove iroha and test_network as dev-dependencies of iroha_client. However, the scope of this task is to produce an MVP with only several tests migrated to this new scheme of running integration tests. Later we can migrate all of the tests, but it's important to provide a framework for new tests first.

We should use this to bring up dockers running iroha for every test.