Scorecard tracking CPU and RSS

[icing]

Track CPU usage and RSS numbers on curl during scorecard runs. Example:

> python3 tests/http/scorecard.py -d h2
...
H2 in curl 8.6.0-DEV ...
Downloads
  Server       Size   single(1x) [cpu/rss]          serial(50x) [cpu/rss]         parallel(50x) [cpu/rss]                Errors
  httpd         1MB      21 MB/s [62.9%/3 MB]          397 MB/s [79.7%/9 MB]          395 MB/s [93.2%/38 MB]              -
  httpd        10MB     176 MB/s [74.3%/7 MB]          924 MB/s [95.8%/20 MB]         616 MB/s [99.8%/343 MB]             -
  httpd       100MB     730 MB/s [95.2%/16 MB]        1098 MB/s [98.7%/19 MB]        1099 MB/s [99.9%/283 MB]             -

[icing]

Now that the h3 report is out, this can be merged.