Improve IBM MQ docs and logging

[AlexandreYang]

What does this PR do?

Improve IBM MQ docs and logging about channel status.

Motivation

I was investing why some channels where not reported.
The reason is that those channels where not used when the check was run, hence not reported.

Additional Notes

Review checklist (to be filled by reviewers)

• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have changelog/ and integration/ labels attached
• Feature or bugfix must have tests
• Git history must be clean
• If PR adds a configuration option, it must be added to the configuration file.

[codecov]

Codecov Report

Merging #4540 into master will decrease coverage by 13.05%.
The diff coverage is 33.33%.

Impacted Files	Coverage Δ
ibm_mq/datadog_checks/ibm_mq/ibm_mq.py	86.66% <33.33%> (-0.98%)	⬇️
datadog_checks_dev/datadog_checks/dev/env.py	55.88% <0%> (-1.27%)	⬇️
...dog_checks_dev/datadog_checks/dev/plugin/pytest.py	21.51% <0%> (ø)	⬆️
riakcs/datadog_checks/riakcs/riakcs.py
oracle/tests/test_oracle.py
twistlock/datadog_checks/twistlock/twistlock.py
linkerd/datadog_checks/linkerd/linkerd.py
...oller/datadog_checks/openstack_controller/utils.py
istio/tests/test_e2e.py
gitlab_runner/tests/test_integration.py
... and 783 more

[FlorianVeaux]

Doesn't that work though?

Suggested change

	$ docker exec -it ibm_mq bash
	$ docker exec -it ibm_mq runmqsc

[AlexandreYang]

Yes, it does, thx for the suggestion :)

Simplified the commands.