Support implementation agnostic mutation testing schema

[nicojs]

If anyone is still using sonar qube, it would be cool if this plugin supported the mutation-testing-report-schema. Making it compatible with (in theory) a big list of mutation testing frameworks. Stryker4s, Stryker.NET, Stryker, PIT, Mull, InfectionPHP, and anyone else that decides to allign on the schema.

https://github.com/stryker-mutator/mutation-testing-elements/tree/master/packages/mutation-testing-report-schema