chat : nemotron thinking & toolcalling support (#15676)
* feat: nemotron thinking & toolcalling support
* Trailing whitespaces
* Corrected template for Nemotron
* Template and parser fixes
* Final template and grammar changes
* Whitespace
* Always do lazy grammar processing since </think> tag will always be there.
* Allow extra content after toolcall
* Whitespace
* New tests: thinking + tools, tools + content, thinking + tools + content (new!)
* Whitespace
* Remove cURL test script
