Nvidia NIM Integration (#18964)

* Create Nvidia NIM scaffolding

* Add Initial Release changelog

* sync models and config

* Add metadata and tests

* Add Readme

* nvidia dash (#19074)

* nvidia dash

* nits

* more nits

* nit

* validate-assets fixes

* remove astericks in README hyperlink ref

* Address nits

* Update metadata desciption for process.start_time_seconds

Co-authored-by: Steven Yuen <steven.yuen@datadoghq.com>

* Add documentation nits

* Final nits

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Co-authored-by: Steven Yuen <steven.yuen@datadoghq.com> 83fb160