common : move arg parser code to `arg.cpp` (#9388)
* common : move arg parser to arg.cpp
* better categorize args
* add cmake
* missing climits
* missing cstdarg
* common : more explicit includes
* fix build
* refactor gpt_params_parse
* update server readme
* fix test
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Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>
