- Add a new test image for Iroha V2 (iroha2-all-in-one). It start a test ledger in single container,
  and also contains a proxy script for running iroha_client_cli.
- Add the new image to the CI.
- Add a new class for starting and interacting with Iroha V2 test ledger
  from typescript test - Iroha2TestLedger.
- Add test for test setup class to ensure basic functions are working correctly.

Relates to hyperledger-cacti#2138

Signed-off-by: Michal Bajer <michal.bajer@fujitsu.com>

- Add new Iroha V2 cactus connector.
- Two OpenAPI endpoints are implemented: `transact` and `query`. Both endpoints support
  critical subset of instructions and queries supported by the upstream javascript iroha sdk.
- One SocketIO endpoint can be used to monitor new blocks from the ledger.
- New connector can be used through a verifier-client interface.
- All added functions are tested in functional test suites and documented.
- Added execution of Iroha2 tests to the CI.

Additional notes:
- Connector doesn't work well with cactus module system, the issue has been reported and described
  in README. PR is not merge-ready until this is fixed (the CI should fail now).
- Iroha V2 javascript packages are not available on official npm yet, had to include `.npmrc` with
  private npm address. I'm not sure if there's ETA of delivering these through NPM, so it might be
  necessary to commit it after all.

Closes hyperledger-cacti#2138
Depends on hyperledger-cacti#2140

Signed-off-by: Michal Bajer <michal.bajer@fujitsu.com>

- Add new endpoint `generate-transaction`, to create unsigned transactions
  that can be signed on the client side.
- Add a function to iroha2-connector package to help signing iroha transactions
  on the client (BLP) side.
- Extend transact endpoint to accept signed transaction as an argument as well.
- Add new test suite to check features implemented in this PR (i.e. signing on the client side).

Relates to hyperledger-cacti#2077

Depends on hyperledger-cacti#2153

Signed-off-by: Michal Bajer <michal.bajer@fujitsu.com>