subscription-manager on RHEL installs a symlink in /usr/bin to
console-helper (part of usermode), which triggers an interactive prompt
for root credentials when run as user. It seems that console-helper
does not handle well non-interactive contexts (e.g. without a TTY for
input), and thus it will hang waiting for input when run as user in an
Ansible task.
Since subscription-manager requires root already anyway (and it will
fail when explicitly run as user), then apply the same logic locally on
all the modules that interact with it: redhat_subscription,
rhsm_release, and rhsm_repository.
