Fix PHP coverage not working correctly in IDE due to output file not being accessible

[Molkobain]

Base information

Question	Answer
Related to a SourceForge thread / Another PR / Combodo ticket?	No
Type of change?	Bug fix

Symptom (bug)

When executing PHP coverage in PHPStorm, it can't access the result file as it is output in the PHP container.

Reproduction procedure (bug)

1. On iTop 3.2.2
2. With PHPStorm as the IDE
3. Launch unit tests with coverage enabled
4. See that the process ends well but it is not displayed

Cause (bug)

With PHPStorm, the XML file is output in /opt/phpstorm-coverage in the PHP container.
PHPStorm running locally can't access the result file.

Proposed solution (bug and enhancement)

Add a new volume to the Docker compose recipe to mount the PHP coverage output folder locally.
Thanks to @Lenaick for pointing this out to me!

Checklist before requesting a review

• I have performed a self-review of my code
• I have tested all changes I made on an iTop instance
• Would a unit test be relevant and have I added it?
• Is the PR clear and detailed enough so anyone can understand without digging in the code?

Checklist of things to do before PR is ready to merge

• Discuss with the team if the env. var. is well named and placed