[Feature Request] Support CPU Cgroup Limits in Resource-based tuner / Confirm memory functionality

[Sushisource]

Is your feature request related to a problem? Please describe.

A few users have expressed a desire to be able to target CPU as a % of CPU limits/quota in containerized environments.

Describe the solution you'd like

Will need to use cgroup functionality to determine CPU usage as a fraction of the container's used CPU vs it's limit/quota.

Additional context

It also appears that the memory usage calculation when in a cgroup environment can be wrong. It seems like maybe the whole-host usage is getting compared against per-container limits and ending up with improperly high usage percentages. If that's the case, fix.

[Sushisource]

There is an impl in Go that can be referenced: https://github.com/temporalio/sdk-go/blob/aecdca8be43def99f6237a07385f58612869cd65/contrib/resourcetuner/cgroups.go#L46

I'm not 100% sure if this is what we want or not, but, it's one option. We probably want to be able to configure how the tuner should calculate usage. IE: Host | CGroups | Whatever

[Sushisource]

Other context: This machinery is all going to get called from the worker insights stats reporting machinery: #1023