Reinstate code coverage

[alexpott]

@aik099 requested this. @stof asked me to remove it from the original MR but thinking about it we should only remove it in the MR the replaces it with psalm / phpstan

[stof]

phpstan and psalm are about static analysis, not about code coverage

[alexpott]

Sure but scutinizer is doing static analysis and presenting the code coverage results. So any MR that removes scutinizer should needs to cope with both I guess.

[stof]

The static analysis performed by scrutinizer is broken anyway. The config still uses the old scrutinizer tool, that is unmaintained since 3 years (the only reason it manages to analyze our code without becoming too crazy is because we still support PHP 5.4, and so we don't use features it does not understand, like scalar typehints).

[aik099]

@stof , so Scrutinizer CI is the past or just its Ocular tool was replaced with something, that works?

For my projects, I've been using CodeCov (https://app.codecov.io) for some time now. This way any static analysis tool can be used.

[Chris53897]

This PR could be closed in my eyes. As Codecov is actual in use