Rename 'cli' used in tests to avoid local test failures

[e2]

Summary

Aruba's Cucumber scenarios uses "cli" as a cli program for testing. On my system, this resolves to the cli utility from the Debian mono-runtime package. This causes tests to fail locally.

Expected Behavior

Aruba's tests should be green, even when run locally.

Current Behavior

Aruba's tests will fail on systems with mono-runtime installed.

Possible Solution

Explained here: #350 (comment)

Basically, it's about replacing: bin/cli invocations with: bin/aruba-test-cmd.

I'll probably get to it - after my other PRs are merged (to avoid merge conflicts since there could be quite a bit of changes here).

The other solution is to use Docker for testing locally (#353).

Steps to Reproduce (for bugs)

1. On Ubuntu install mono-runtime
2. Run Cucumber tests on Aruba's master branch
3. Tests expecting /bin/cli to not exist will strangely fail.

Context

Failing local tests discourage from contributing.