Draft: Properly parse boolean variables

Kpet variables are only provided as strings. Everywhere else, booleans are parsed with misc.strtobool, which only accepts false/False/true/True.

For consistency and resilience, use that method in kpet as well via an is_true filter. This mirrors the shell function with the same name in cki_lib.cki_utils and the already existing method import in the jinja templating in cki_tools.cki.deployment_tools.render.

Signed-off-by: Michael Hofmann mhofmann@redhat.com