* Implement passthrough for benchmark
Add a new option -p,--passthrough to benchmark.
With this option, the benchmark command prints its results to stdout and passes the block's output to the next command in the pipeline.
* Add execution block for benchmark -p
`benchmark --passthrough` now takes a block where the benchmark output is sent.
Example:
`benchmark -p {save bench.toml} {ls}`
* Add system, user and idle times to benchmark command
* Feature-gate dependency on heim in benchmark
* Reorder let bindings in benchmark
* Fully feature-gate rich-benchmark and print 0sec on zero duration
