Implement the import and export handlers for Custodia keys as external
scripts. It's a prerequisite to drop DAC override permission and proper
SELinux rules for ipa-custodia.
Except for DMLDAP, handlers no longer run as root but as handler
specific users with reduced privileges. The Dogtag-related handlers run
as pkiuser, which also help with HSM support.
The export and import handles are designed to be executed by sudo, too.
In the future, ipa-custodia could be executed as an unprivileged process
that runs the minimal helper scripts with higher privileges.
Fixes: https://pagure.io/freeipa/issue/6888
Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
