Have GitLab Runner package installation ignore skel when creating user home directory
We allow users to install GitLab Runner using a [package repository[(https://docs.gitlab.com/runner/install/linux-repository.html), which creates a home directory and has the defaults skeleton directory specified in the machine. Debian buster breaks this because of the .bash_logout (issue #4449). In !1523 we added a flag
GITLAB_RUNNER_DISABLE_SKEL which allows user to remove the skel and have the home directory empty for the
This flag is turned off by default for now to prevent breaking change.
GITLAB_RUNNER_DISABLE_SKEL by default in %13.0 to prevent issues like this ever happening, if the user wants to have the skel generate they have to pass the flag explicitly.