Calculate VMRSS adjustments dynamically as OOM_SCORE_*/1000 of total memory

[RanHuang]

This commit adds a new --vmrss-adjust-percent command-line option that allows users to set the VMRSS adjustment value as a percentage of total memory instead of using the fixed 3 GiB default.

Key changes:

• Add --vmrss-adjust-percent option to set VMRSS adjustment as percentage
  of total memory for --prefer/--avoid processes when using --sort-by-rss
• Store vmrss_adjust_percent and total_memory_kib in poll_loop_args_t
• Calculate dynamic VMRSS adjustments based on percentage if specified
• Maintain backward compatibility with fixed 3 GiB default values
• Update documentation in MANPAGE.md and README.md
• Add validation for percentage value (0-100)

[RanHuang]

Execution Results and Test Screenshots

[rfjakob]

Hi, thanks, but I don't think this should be adjustable.

Please, instead, change it to add or subtract OOM_SCORE_PREFER/1000 of total memory. This will make --sort-by-rss match what happens without --sort-by-rss.

[RanHuang]

I've made adjustments according to your suggestion, using OOM_SCORE_PREFER and OOM_SCORE_AVOID to calculate the VMRSS adjustment values.