[REQUEST] Stats filtered per cgroup container/namespace

[abelpc]

Is your feature request related to a problem? Please describe.
No.

Describe the solution you'd like
All statistics already present in btop, but filtered in a per-cgroup basis.

Describe alternatives you've considered
top and htop are tools that can show which cgroup container a process is running on, but that's about it.

Additional context
In a context where containers (Docker, LXC, podman, containerd, etc.) are commonly used, I believe having the ability to filter statistics for each container for debugging purposes is a 'must' feature to have.

[Atrate]

Partially related (in spirit, not in the underlying technology): #418