common: support negated args (#17919)

* args: support negated args

* update docs

* fix typo

* add more neg options

* Apply suggestions from code review

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

* rm duplicated arg

* fix LLAMA_ARG_NO_HOST

* add test

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Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

Author: ngxson