Allow uninstalling packages via apt addon on Container Based Infrastructure

[pali]

Sometimes it is necessary to uninstall some preinstalled packages. On sudo-enabled VM based builds it is possible via sudo apt-get remove and it is working fine. But sudo apt-get remove is not available on Container Based Infrastructure therefore this functionality needs to be present in apt addon, which already handles installing of packages.

[stale]

Thanks for contributing to this issue. As it has been 90 days since the last activity, we are automatically closing the issue. This is often because the request was already solved in some way and it just wasn't updated or it's no longer applicable. If that's not the case, please do feel free to either reopen this issue or open a new one. We'll gladly take a look again! You can read more here: https://blog.travis-ci.com/2018-03-09-closing-old-issues

[pali]

This issue is still valid.