TestingTools gitignore file added

This .gitignore file aims to avoid those autogenerated files and folders from testing tools such as SonarQube, Sphinx, PyCov... It's not a complete file, but if everyone add some of those files that they have to ignore manually, the file will be useful for a wider range of developers.

For me it works fine as I use mostly these tools in my projects, but of course there must a lot more.