Set up code coverage and code quality mechanism

[kghbln]

It appears that code coverage and code quality integration is not yet set up. Thus I removed the badges from the README prior to making the 1.0.0 release. Once this is set up ...

[![Code Coverage](https://scrutinizer-ci.com/g/SemanticMediaWiki/Mermaid/badges/coverage.png?b=master)](https://scrutinizer-ci.com/g/SemanticMediaWiki/Mermaid/?branch=master)
[![Scrutinizer Code Quality](https://scrutinizer-ci.com/g/SemanticMediaWiki/Mermaid/badges/quality-score.png?b=master)](https://scrutinizer-ci.com/g/SemanticMediaWiki/Mermaid/?branch=master)

[samwilson]

If the repo moved to Gerrit, it could be set up with the standard extensions' CI tools. Would that be an option?

[kghbln]

If the repo moved to Gerrit, it could be set up with the standard extensions' CI tools. Would that be an option?

No, at least not for me. Personally I'd rather have no quality mechanism than moving this to Gerrit. I may be overruled by the extension's maintainer but ...