Limiting env vars, docker&k8s labels, and weave net connection entries
to 20 is problematic because
- the truncation is arbitrary - there is a good chance that if you
care about a specific entry it won't be there
- the truncation is not consistent - different entries get truncated
at different times
- some of the rendering logic depends on specific labels, for example
namespace filtering of containers depends on the
`io.kubernetes.pod.namespace` label.
In practice, there should never be a huge number of labels, or Weave
Net connection entries. So there is no need to truncate them.
That leaves env vars. These are of limited use, so we now omit them by
default. If they are included they are included in full, so they are
actually useful.
Fixes#3127
* Show k8s labels and container env vars in the details panel.
* Add show more bar to the env vars and labels
* React key was in the wrong place; empty tables render section labels.