Add container_creation_time_seconds (previously: container_start_time_seconds); use runtime start time for container_start_time_seconds (podman & docker)

[ultinous-akos]

fixes #3688

[iwankgb]

Do you mind adding this feature to other handlers too?

[ultinous-akos]

Do you mind adding this feature to other handlers too?

@iwankgb
For now, i would prefer to keep this PR focused on the Docker and Podman handlers, since that's where I verified the issue and the fix.

[dims]

i think at a minimum we'll need containerd too

[dims]

we now have a integration test and a way to run it locally as well that covers both docker and containerd metrics - #3819