Add metrics to performance report + document in docs

[jfomhover]

Updating the list of metrics reported by perf report at the end of the job for both single node and mpi multi node:

• added a couple more metrics to understand cpu utilization in detail
• renamed some of them for better precision
• creates documentation with an explicit definition.
• fix "disk write" metric (was using count instead of bytes)

[github-actions[bot]]

Unit Test Results for Build

    1 files  ±0      1 suites  ±0   1m 22s :stopwatch: +6s 111 tests ±0  111 :heavy_check_mark: ±0  0 :zzz: ±0  0 :x: ±0 

Results for commit 0dea80ca. ± Comparison against base commit 17b53771.

:recycle: This comment has been updated with latest results.

[github-actions[bot]]

Package	Line Rate	Branch Rate	Complexity
common	83%	0%	0
pipelines.azureml	80%	0%	0
scripts	100%	0%	0
scripts.data_processing.generate_data	92%	0%	0
scripts.data_processing.lightgbm_data2bin	95%	0%	0
scripts.data_processing.partition_data	92%	0%	0
scripts.inferencing.custom_win_cli	94%	0%	0
scripts.inferencing.lightgbm_c_api	75%	0%	0
scripts.inferencing.lightgbm_python	95%	0%	0
scripts.inferencing.lightgbm_ray	95%	0%	0
scripts.inferencing.treelite_python	94%	0%	0
scripts.model_transformation.treelite_compile	92%	0%	0
scripts.sample	93%	0%	0
scripts.training.lightgbm_python	77%	0%	0
scripts.training.lightgbm_ray	88%	0%	0
Summary	85% (1879 / 2219)	0% (0 / 0)	0