<details open> args: refactor mlock/mmap/directio into load-mode (#20834) * args: overhaul mmap/mlock/dio into single arg Signed-off-by: Aaron Teo <aaron.teo1@ibm.com> * docs: update docs with llama-gen-docs Signed-off-by: Aaron Teo <aaron.teo1@ibm.com> * chore: satisfy code quality Signed-of