Further Piwik.org => Matomo.org replacements #12415
Those are only some replacements. Further changes will be needed to made later such as:
We also need to see how to handle things like
Those things will all be done in other PRs. This PR only updates some links from piwik.org => matomo.org and some mentions of Piwik to Matomo. Also puts widgets from "About Piwik" to "About Matomo".
I expect a lot of tests will needed to be fixed and updated.