common : refactor arg parser (#9308)
* (wip) argparser v3
* migrated
* add test
* handle env
* fix linux build
* add export-docs example
* fix build (2)
* skip build test-arg-parser on windows
* update server docs
* bring back missing --alias
* bring back --n-predict
* clarify test-arg-parser
* small correction
* add comments
* fix args with 2 values
* refine example-specific args
* no more lamba capture
Co-authored-by: [email protected]
* params.sparams
* optimize more
* export-docs --> gen-docs
