WIP: d/t/boot-and-services: skip/ignore some expected failures in container

Some services/operations are expected to fail inside an unprivileged container; ignore the failures or skip the tests.

Specifically: -skip the AppArmorTest() if in_container This shouldn't need any upstream change -in test_no_failed(), ignore systemd-journald-audit service failure There is already an upstream bug open for this, https://github.com/systemd/systemd/issues/6519

• in test_no_failed(), ignore sys-kernel-config.mount failure There is no upstream bug open for this - maybe there should be. Ubuntu already carries a patch to work around it, https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/tree/debian/patches/debian/UBUNTU-units-block-CAP_SYS_MODULE-units-in-containers-too.patch