* add test
* fix no_sync bug in low level zero plugin
* fix test
* add argument for grad accum
* add grad accum in backward hook for gemini
* finish implementation, rewrite tests
* fix test
* skip stuck model in low level zero test
* update doc
* optimize communication & fix gradient checkpoint
* modify doc
* cleaning codes
* update cpu adam fp16 case
* [doc] fix title of mixed precision
* [doc]update document of zero with chunk
* [doc] update document of zero with chunk, fix
* [doc] update document of zero with chunk, fix
* [doc] update document of zero with chunk, fix
* [doc] update document of zero with chunk, add doc test
* [doc] update document of zero with chunk, add doc test
* [doc] update document of zero with chunk, fix installation
* [doc] update document of zero with chunk, fix zero with chunk doc
* [doc] update document of zero with chunk, fix zero with chunk doc