* Update metric names to match current release.
* Improve descriptions.
* Improve examples to show more query language functionality.

Memory:
* Show use of `or` function.
* Automatically select "MemAvailable" kernel metric if possible.

CPU:
* Show use of `avg without ...`.
* Show CPU utilization per node.

Network:
* Show use of `!=` label matching.
* Don't show "localhost" metrics.