MQE-1541: Documentation for debug changes

[soumyau]

Added documentation for https://jira.corp.magento.com/browse/MQE-1541

Description

Fixed Issues (if relevant)

1. magento/magento2-functional-testing-framework#<issue_number>: Issue title
2. ...

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/verification tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)
• Changes to Framework doesn't have backward incompatible changes for tests or have related Pull Request with fixes to tests

[KevinBKozan]

@dobooth content-wise, PR is good. I think it needs some formatting work which I leave in your capable hands

[coveralls]

Coverage remained the same at 54.395% when pulling 5f0e625 on MQE-1541 into a779d9b on develop.

[coveralls]

Coverage increased (+1.6%) to 55.958% when pulling 2e92c25 on MQE-1541 into 958e9c3 on develop.

[coveralls]

Coverage increased (+1.6%) to 55.958% when pulling 2e92c25 on MQE-1541 into 958e9c3 on develop.