[1.1] libct/cg: add misc controller to v1 drivers

[kolyshkin]

This is just so that

• the container can join the misc controller;
• the `Destroy() can actually remove the cgroup.

This should fix the issue reported in kubernetes/kubernetes#112124 (comment)

(cherry picked from commit 611bbac / PR #3815.

Proposed changelog entry:

- Bare minimal support for cgroup v1 misc controller. (#3823)

[kolyshkin]

This fixes the issue with Kubernetes and recent kernel adding misc controller.. I'm not exactly sure how misc controller is being created, but it's not being joined to or removed since runc knows nothing about it.

[cyphar]

We probably want to make a proper MiscCgroup controller at some point since it's a real controller (I'm still not sure why it wasn't added to /sys/fs/resctl since that was created the last time a CPU-specific feature cgroup controller was proposed). But yeah, this is fine as a minimal implementation.

[cyphar]

LGTM.