Deprecating Piwik::setUserHasSuperUserAccess() and switching to Access::doAsSuperUser().
Fixing UI tests and adding tests for Access::doAsSuperUser.
Remove @Only group used in debugging.
Fix installation process, missing super user access for some calls.
Merge pull request #6342 from piwik/set_superuser_access_refactor

Remove and deprecate Piwik::setUserHasSuperUserAccess() and switch to using Access::doAsSuperUser()